# UNITED	STATES

# SECURITIES	AND	EXCHANGE	COMMISSION

(Mark	One)

# ANNUAL	REPORT	PURSUANT	TO	SECTION	13	OR	15(d)	OF	THE

# SECURITIES	EXCHANGE	ACT	OF	1934

For	the	fiscal	year	ended	December	31,	2018

# TRANSITION	REPORT	PURSUANT	TO	SECTION	13	OR	15(d)	OF	THE

# Commission	file	number:	1-7933

# Aon	plc

(Exact	name	of	registrant	as	specified	in	its	charter)

ENGLAND	AND	WALES

	(State	or	Other	Jurisdiction	of Incorporation	or	Organization)

122	LEADENHALL	STREET,	LONDON,	ENGLAND 	(Address	of	principal	executive	offices)

(Registrant's	Telephone	Number,	Including	Area	Code)

Securities	registered	pursuant	to	Section	12(b)	of	the	Act:

# Title	of	Each	Class

Class	A	Ordinary	Shares,	$0.01	nominal	value

Name	of	Each	Exchange on	Which	Registered

New	York	Stock	Exchange

# Securities	registered	pursuant	to	Section	12(g)	of	the	Act:	NONE

Indicate	by	check	mark	if	the	registrant	is	a	well-known	seasoned	issuer,	as	defined	in	Rule	405	of	the	Securities	Act.	YES	 ý	NO	o

Indicate	by	check	mark	if	the	registrant	is	not	required	to	file	reports	pursuant	to	Section	13	or	Section	15(d)	of	the	Exchange	Act.	YES o	NO	ý

Indicate	by	check	mark	whether	the	registrant	(1)	has	filed	all	reports	required	to	be	filed	by	Section	13	or	15(d)	of	the	Securities	Exchange	Act	of	1934	during	the	preceding	12	months	(or	for such	shorter	period	that	the	registrant	was	required	to	file	such	reports),	and	(2)	has	been	subject	to	such	filing	requirements	for	the	past	90	days.	YES	ý	NO	o

Indicate	by	check	mark	whether	the	registrant	has	submitted	electronically	every	Interactive	Data	File	required	to	be	submitted	pursuant	to	Rule	405	of	Regulation	S-T	(§232.405	of	this	chapter) during	the	preceding	12	months	(or	for	such	shorter	period	that	the	registrant	was	required	to	submit	such	files).	YES	ý	NO	o

Indicate	by	check	mark	if	disclosure	of	delinquent	filers	pursuant	to	Item	405	of	Regulation	S-K	is	not	contained	herein,	and	will	not	be	contained,	to	the	best	of	registrant's	knowledge,	in definitive	proxy	or	information	statements	incorporated	by	reference	in	Part	III	of	this	Form	10-K	or	any	amendment	to	this	Form	10-K.	o

Indicate	by	check	mark	whether	the	registrant	is	a	large	accelerated	filer,	an	accelerated	filer,	a	non-accelerated	filer,	a	smaller	reporting	company,	or	an	emerging	growth	company.	See	the definitions	of	"large	accelerated	filer,"	"accelerated	filer,"	"smaller	reporting	company,"	and	"emerging	growth	company"	in	Rule	12b-2	of	the	Exchange	Act.

Large	accelerated	filer	ý Accelerated	filer	o

Non-accelerated	filer	o

Smaller	reporting	company	o Emerging	growth	company	o

If	an	emerging	growth	company,	indicate	by	check	mark	if	the	registrant	has	elected	not	to	use	the	extended	transition	period	for	complying	with	any	new	or	revised	financial	accounting standards	provided	pursuant	to	Section	13(a)	of	the	Exchange	Act.	o

Indicate	by	check	mark	whether	the	registrant	is	a	shell	company	(as	defined	in	Rule	12b-2	of	the	Exchange	Act).	YES	 o	NO	ý

As	of	June	29,	2018,	the	aggregate	market	value	of	the	registrant's	Class	A	Ordinary	Shares	held	by	non-affiliates	of	the	registrant	was	 $33,332,666,779	based	on	the	closing	sales	price	as reported	on	the	New	York	Stock	Exchange	—	Composite	Transaction	Listing.

# DOCUMENTS	INCORPORATED	BY	REFERENCE

Portions	of	Aon	plc's	Proxy	Statement	for	the	2019	Annual	General	Meeting	of	Shareholders	to	be	held	on	 June	21,	2019	are	incorporated	by	reference	in	this	Form	10-K	in	response	to	Part	III, Items	10,	11,	12,	13	and	14.

# Table	of	Contents

# PART	I

Item	1.	Business

Item	1A.	Risk	Factors Item	1B.	Unresolved	Staff	Comments Item	2.	Properties Item	3.	Legal	Proceedings Item	4.	Mine	Safety	Disclosure

# PART	II

Item	5.	Market	for	Registrant's	Common	Equity,	Related	Stockholder	Matters	and	Issuer	Purchases	of	Equity	Securities

Item	6.	Selected	Financial	Data

Item	7.	Management's	Discussion	and	Analysis	of	Financial	Condition	and	Results	of	Operations

# Item	7A.	Quantitative	and	Qualitative	Disclosures	About	Market	Risk

# Item	8.	Financial	Statements	and	Supplementary	Data

# Aon	plc	Consolidated	Statements	of	Income

# Aon	plc	Consolidated	Statements	of	Comprehensive	Income

# Aon	plc	Consolidated	Statements	of	Financial	Position

# Aon	plc	Consolidated	Statements	of	Shareholders'	Equity

# Aon	plc	Consolidated	Statements	of	Cash	Flows

# Notes	to	Consolidated	Financial	Statements

Item	9.	Changes	in	and	Disagreements	with	Accountants	on	Accounting	and	Financial	Disclosure Item	9A.	Controls	and	Procedures

# Item	9B.	Other	Information

# PART	III

Item	10.	Directors,	Executive	Officers	and	Corporate	Governance

Item	11.	Executive	Compensation

Item	12.	Security	Ownership	of	Certain	Beneficial	Owners	and	Management	and	Related	Stockholder	Matters Item	13.	Certain	Relationships	and	Related	Transactions,	and	Director	Independence Item	14.	Principal	Accountant	Fees	and	Services

# PART	IV

Item	15.	Exhibits	and	Financial	Statement	Schedules

SIGNATURES

# OVERVIEW

Aon	plc	(which	may	be	referred	to	as	"Aon,"	the	"Company,"	"we,"	"us,"	or	"our")	is	a	leading	global	professional	services	firm	that	provides	advice	and	solutions to	clients	focused	on	risk,	retirement,	and	health,	delivering	distinctive	client	value	via	innovative	and	effective	risk	management	and	workforce	productivity	solutions that	are	under-pinned	by	industry-leading	data	and	analytics.	Our	strategy	is	to	be	the	preeminent	professional	services	firm	in	the	world,	focused	on	risk	and	people.

Our	clients	are	globally	diversified	and	include	all	market	segments	(individuals	through	personal	lines,	mid-market	companies,	and	large	global	companies)	and almost	every	industry	in	over	120	countries	and	sovereignties.	This	diversification	of	our	customer	base	helps	provide	us	stability	in	different	economic	scenarios	that could	affect	specific	industries,	customer	segments,	or	geographies.

We	have	continued	to	focus	our	portfolio	on	higher-margin,	capital-light	professional	services	businesses	that	have	high	recurring	revenue	streams	and	strong	cash flow	generation.	We	endeavor	to	make	capital	allocation	decisions	based	upon	return	on	invested	capital	("ROIC").

# BUSINESS	SEGMENT

Beginning	in	the	first	quarter	of	2017	and	following	the	sale	of	our	benefits	administration	and	business	process	outsourcing	business	(the	"Divested	Business")	on May	1,	2017,	the	Company	led	a	set	of	initiatives	designed	to	strengthen	Aon	and	unite	the	firm	with	one	portfolio	of	capability	enabled	by	proprietary	data	and	analytics and	one	operating	model	to	deliver	additional	insight,	connectivity,	and	efficiency.	These	initiatives	reinforce	Aon's	ROIC	decision-making	process	and	emphasis	on free	cash	flow.	The	Company	is	now	operating	as	one	segment	that	includes	all	of	Aon's	continuing	operations,	which,	as	a	global	professional	services	firm,	provides advice	and	solutions	to	clients	focused	on	risk,	retirement,	and	health	through	five	principal	products	and	services:	Commercial	Risk	Solutions,	Reinsurance	Solutions, Retirement	Solutions,	Health	Solutions,	and	Data	&	Analytic	Services.	Collectively,	these	products	and	service	revenue	lines	make	up	our	one	segment:	Aon	United.

In	2018	our	consolidated	total	revenue	was	$10,770	million.	This	includes	$4,652	million	in	Commercial	Risk	Solutions,	$1,563	million	in	Reinsurance	Solutions, $1,865	million	in	Retirement	Solutions,	$1,596	million	in	Health	Solutions,	and	$1,105	million	in	Data	&	Analytic	Services,	before	intercompany	eliminations.

# Principal	Products	and	Services

Commercial	Risk	Solutions	includes	retail	brokerage,	cyber	solutions,	global	risk	consulting,	and	captives.		In	retail	brokerage,	our	team	of	expert	risk	advisors applies	a	client-focused	approach	to	commercial	risk	products	and	services	that	leverage	Aon's	global	network	of	resources,	industry-leading	data	and	analytics,	and specialized	expertise.	Cyber	solutions	is	one	of	the	industry's	premier	resources	in	cyber	risk	management.	Our	strategic	focus	extends	to	identify	and	protect	critical digital	assets	supported	by	best-in-class	transactional	capabilities,	enhanced	coverage	expertise,	deep	carrier	relationships,	and	incident	response	expertise.		Global	risk consulting	 is	 a	 world-leading	 provider	 of	 risk	 consulting	 services	 supporting	 clients	 to	 better	 understand	 and	 manage	 their	 risk	 profile	 through	 identifying	 and quantifying	the	risks	they	face.	We	assist	clients	with	the	selection	and	implementation	of	the	appropriate	risk	transfer,	risk	retention,	and	risk	mitigation	solutions,	and ensure	the	continuity	of	their	operations	through	claims	consulting.	Captives	is	a	leading	global	captive	insurance	solutions	provider	that	manages	over	1,100	insurance entities	worldwide	including	captives,	protected	segregated	and	incorporated	cell	facilities,	as	well	as	entities	that	support	insurance-linked	securities	and	specialist insurance	and	reinsurance	companies.

Reinsurance	Solutions	includes	treaty	and	facultative	reinsurance	and	capital	markets.	Treaty	reinsurance	addresses	underwriting	and	capital	objectives	on	a portfolio	level,	allowing	our	clients	to	more	effectively	manage	the	combination	of	premium	growth,	return	on	capital,	and	rating	agency	interests.	This	includes	the development	of	more	competitive,	innovative,	and	efficient	risk	transfer	options.	Facultative	reinsurance	empowers	clients	to	better	understand,	manage,	and	transfer risk	through	innovative	facultative	solutions	and	provides	the	most	efficient	access	to	the	global	facultative	reinsurance	markets.	Capital	markets	is	a	global	investment bank	with	expertise	in	mergers	and	acquisitions,	capital	raising,	strategic	advice,	restructuring,	recapitalization	services,	and	insurance-linked	securities.	We	partner	with insurers,	reinsurers,	investment	firms,	banks,	and	corporations	in	the	management	of	complex	commercial	issues	through	the	provision	of	corporate	finance	advisory services,	capital	markets	solutions,	and	innovative	risk	management	products.

Retirement	Solutions includes	 core	 retirement,	 investment	 consulting,	 and	 talent,	 rewards,	 and	 performance.	 Retirement	 consulting	 specializes	 in	 providing organizations	across	the	globe	with	strategic	design	consulting	on	their	retirement	programs,	actuarial	services,	and	risk	management,	including	pension	de-risking, governance,	integrated	pension	administration,	and	legal	and	compliance	consulting.	Investment	consulting	provides	public	and	private	companies	and	other	institutions with	advice	on

developing	and	maintaining	investment	programs	across	a	broad	range	of	plan	types,	including	defined	benefit	plans,	defined	contribution	plans,	endowments,	and foundations.	Our	delegated	investment	solutions	offer	ongoing	management	of	investment	programs	and	fiduciary	responsibilities	either	in	a	partial	or	full	discretionary model	for	multiple	asset	owners.	It	partners	with	clients	to	deliver	our	scale	and	experience	to	help	them	effectively	manage	their	investments,	risk,	and	governance	and potentially	lower	costs.	Talent,	rewards,	and	performance	delivers	advice	and	solutions	that	help	clients	accelerate	business	outcomes	by	improving	the	performance	of their	people.	It	supports	the	full	employee	lifecycle,	including	assessment	and	selection	of	the	right	talent,	optimized	deployment	and	engagement,	and	the	design, alignment,	and	benchmarking	of	compensation	to	business	strategy	and	performance	outcomes.

Health	Solutions	includes	heath	and	benefits	brokerage	and	health	care	exchanges.	Health	and	benefits	brokerage	partners	with	employers	to	develop	innovative, customized	benefits	strategies	that	help	manage	risk,	drive	engagement,	and	promote	accountability.	Our	private	health	exchange	solutions	help	employers	transform how	they	sponsor,	structure,	and	deliver	health	benefits	by	building	and	operating	a	cost	effective	alternative	to	traditional	employee	and	retiree	health	care.	We	seek outcomes	of	reduced	employer	costs,	risk,	and	volatility,	alongside	greater	coverage	and	plan	choices	for	individual	participants.

Data	&	Analytic	Services	includes	Affinity,	Aon	InPoint,	and	ReView.	Affinity	specializes	in	developing,	marketing	and	administering	customized	insurance programs	and	specialty	market	solutions	for	Affinity	organizations	and	their	members	or	affiliates.	Aon	InPoint	draws	on	the	Global	Risk	Insight	Platform,	one	of	Aon's proprietary	databases,	and	is	dedicated	to	making	insurers	more	competitive	by	providing	data,	analytics,	engagement,	and	consulting	services.	ReView	draws	on	another Aon	proprietary	database	and	broker	market	knowledge	to	provide	advisory	services,	analysis,	and	benchmarking	to	help	reinsurers	more	effectively	meet	the	needs	of cedents	through	the	development	of	more	competitive,	innovative,	and	efficient	risk	transfer	options.

# Revenue	and	Compensation

Our	business	generates	revenues	primarily	through	commissions,	compensation	from	insurance	and	reinsurance	companies	for	services	we	provide	to	them,	and	fees from	customers.	Commissions	and	fees	for	brokerage	services	vary	depending	upon	several	factors,	which	may	include	the	amount	of	premium,	the	type	of	insurance	or reinsurance	coverage	provided,	the	particular	services	provided	to	a	client,	insurer,	or	reinsurer,	and	the	capacity	in	which	we	act.	Compensation	from	insurance	and reinsurance	companies	includes:	(1)	fees	for	consulting	and	analytics	services,	and	(2)	fees	and	commissions	for	administrative	and	other	services	provided	to	or	on behalf	of	insurers.	Fees	from	clients	for	advice	and	consulting	services	are	dependent	on	the	extent	and	value	of	the	services	we	provide.	Payment	terms	are	consistent with	current	industry	practices.

# Fiduciary	Funds

We	typically	hold	funds	on	behalf	of	clients,	including	premiums	received	from	clients	and	claims	due	to	clients	that	are	in	transit	to	and	from	insurers.	Certain funds	held	on	behalf	of	clients	are	invested	in	interest-bearing	premium	trust	accounts	and	can	fluctuate	significantly	depending	on	when	we	collect	and	remit	cash.	The principal	is	segregated	and	not	available	for	general	operating	purposes,	though	we	earn	interest	on	these	accounts.

# Competition

Our	business	operates	in	a	highly	competitive	and	fragmented	environment.	We	compete	with	other	global	insurance	brokers	and	consulting	companies,	including Marsh	&	McLennan	Companies,	Inc.,	Willis	Towers	Watson	Public	Limited	Company,	Arthur	J	Gallagher	&	Company,	and	Jardine	Lloyd	Thompson	Group	plc,	as	well as	numerous	specialist,	regional,	and	local	firms	in	almost	every	area	of	our	business.	We	also	compete	with	insurance	and	reinsurance	companies	that	market	and service	their	insurance	products	without	the	assistance	of	brokers	or	agents,	and	with	other	businesses	that	do	not	fall	into	the	categories	above,	including	large	financial institutions	and	independent	consulting	firms	and	consulting	organizations	affiliated	with	accounting,	information	systems,	technology,	and	financial	services	firms.

# Seasonality

Due	to	buying	patterns	and	delivery	of	certain	products	in	the	markets	we	serve,	revenues	recognized	tend	to	be	higher	in	the	first	and	fourth	quarters	of	each	fiscal year.

# Licensing	and	Regulation

Our	business	activities	are	subject	to	licensing	requirements	and	extensive	regulation	under	the	laws	of	countries	in	which	we	operate,	including	United	States ("U.S.")	federal	and	state	laws.	See	the	"Risk	Factors"	section	in	Part	I,	Item	1A	of	this	report	for	information	regarding	how	actions	by	regulatory	authorities	or	changes in	legislation	and	regulation	in	the	jurisdictions	in	which	we	operate	may	have	an	adverse	effect	on	our	business.

Regulatory	authorities	in	the	countries	and	states	in	the	U.S.	in	which	our	operating	subsidiaries	conduct	business	may	require	individual	or	company	licenses	to	act as	producers,	brokers,	agents,	third-party	administrators,	managing	general	agents,	reinsurance	intermediaries,	or	adjusters.	Under	the	laws	of	most	countries	and	states, regulatory	authorities	have	relatively	broad	discretion	with	respect	to	granting,	renewing,	and	revoking	producers',	brokers',	and	agents'	licenses	to	transact	business	in the	country	or	state.	The	operating	terms	may	vary	according	to	the	licensing	requirements	of	the	particular	country	or	state,	which	may	require,	among	other	things,	that a	firm	operates	in	the	country	or	state	through	a	local	corporation.	In	a	few	countries	and	states,	licenses	may	be	issued	only	to	individual	residents	or	locally	owned business	entities.	In	such	cases,	our	subsidiaries	either	have	such	licenses	or	have	arrangements	with	residents	or	business	entities	licensed	to	act	in	the	country	or	state.

Our	subsidiaries	must	comply	with	laws	and	regulations	of	the	jurisdictions	in	which	they	do	business.	These	laws	and	regulations	are	enforced	by	the	Financial Conduct	Authority	("FCA")	in	the	United	Kingdom	("U.K."),	by	federal	and	state	agencies	in	the	U.S.,	and	by	various	regulatory	agencies	and	other	supervisory authorities	in	other	countries	through	the	granting	and	revoking	of	licenses	to	do	business,	the	licensing	of	agents,	the	monitoring	of	trade	practices,	policy	form approval,	limits	on	commission	rates,	and	mandatory	remuneration	disclosure	requirements.

Insurance	authorities	in	the	U.K.,	U.S.,	and	certain	other	jurisdictions	in	which	our	subsidiaries	operate	have	enacted	laws	and	regulations	governing	the	investment of	funds,	such	as	premiums	and	claims	proceeds,	held	in	a	fiduciary	capacity	for	others.	These	laws	and	regulations	generally	require	the	segregation	of	these	fiduciary funds	and	limit	the	types	of	investments	that	may	be	made	with	them.

Investment,	securities,	and	futures	licensing	authorities	also	govern	certain	of	our	business	activities.	For	example,	in	the	U.S.,	we	use	Aon	Securities,	LLC,	a	U.S.- registered	broker-dealer	and	investment	advisor,	member	of	the	Financial	Industry	Regulatory	Authority	("FINRA")	and	Securities	Investor	Protection	Corporation,	and an	indirect,	wholly	owned	subsidiary	of	Aon,	for	capital	management	transaction	and	advisory	services	and	other	broker-dealer	activities.	Similar	operations	exist	in other	jurisdictions	outside	of	the	U.S.

Further,	pension	and	financial	laws	and	regulations,	including	oversight	and	supervision	by	the	FCA	in	the	U.K.,	the	Securities	and	Exchange	Commission	("SEC") in	the	U.S.,	and	regulators	in	other	countries	govern	certain	of	the	retirement-related	consulting	services	provided	by	Aon	and	its	subsidiaries	and	affiliates.	This	includes Aon	subsidiaries	that	provide	investment	advisory	services	regulated	by	various	U.S.	federal	authorities	including	the	SEC	and	FINRA,	as	well	as	authorities	on	the	state level.	In	addition,	other	services	provided	by	Aon	and	its	subsidiaries	and	affiliates,	such	as	trustee	services	and	retirement	and	employee	benefit	program	administrative services,	are	subject	in	various	jurisdictions	to	pension,	investment,	securities,	and	insurance	laws	and	regulations,	and	supervision.

# Clientele

Our	clients	operate	in	many	businesses	and	industries	throughout	the	world.	No	one	client	accounted	for	more	than	1%	of	our	consolidated	total	revenues	in	2018. Additionally,	we	place	insurance	with	many	insurance	carriers,	none	of	which	individually	accounted	for	more	than	10%	of	the	total	premiums	we	placed	on	behalf	of our	clients	in	2018.

# Employees

At	December	31,	2018,	we	employed	approximately	50,000	employees	and	conducted	our	operations	through	various	subsidiaries	in	more	than	120	countries	and sovereignties.

# Information	Concerning	Forward-Looking	Statements

This	Annual	Report	on	Form	10-K	contains	certain	statements	related	to	future	results,	or	states	our	intentions,	beliefs,	and	expectations	or	predictions	for	the future,	which	are	forward-looking	statements	as	that	term	is	defined	in	the	Private	Securities	Litigation	Reform	Act	of	1995.	Forward-looking	statements	represent management's	expectations	or	forecasts	of	future	events.	Forward-looking	statements	are	typically	identified	by	words	such	as	"anticipate,"	"believe,"	"estimate," "expect,"	"forecast,"	"project,"	"intend,"	"plan,"	"probably,"	"potential,"	"looking	forward,"	"continue,"	and	other	similar	terms,	and	future	or	conditional	tense	verbs like	"could,"	"may,"	"might,"	"should,"	"will,"	and	"would."	You	can	also	identify	forward-looking	statements	by	the	fact	that	they	do	not	relate	strictly	to	historical	or current	facts.	For	example,	we	may	use	forward-looking	statements	when	addressing	topics	such	as:	market	and	industry	conditions,	including	competitive	and	pricing trends;	 changes	 in	 our	 business	 strategies	 and	 methods	 of	 generating	 revenue;	 the	 development	 and	 performance	 of	 our	 services	 and	 products;	 changes	 in	 the composition	or	level	of	our	revenues;	our	cost	structure	and	the	outcome	of	cost-saving	or	restructuring	initiatives;	the	outcome	of	contingencies;	dividend	policy;	the expected	impact	of	acquisitions	and	dispositions;	pension	obligations;	cash	flow	and	liquidity;	expected	effective	tax	rate;	future	actions	by	regulators;	and	the	impact	of changes	in	accounting	rules.	These	forward-looking	statements	are	subject	to	certain	risks	and	uncertainties	that	could	cause	actual	results	to	differ	materially	from	either historical	or	anticipated	results	depending	on	a	variety	of	factors.	Potential	factors,	which	may	be	revised	or	supplemented	in	subsequent	reports	filed	or	furnished	with the	SEC,	that	could	impact	results	include:

•general	economic	and	political	conditions	in	the	countries	in	which	we	do	business	around	the	world,	including	the	U.K.'s	expected	withdrawal	from	the European	Union;

•changes	 in the competitive environment or damage to our reputation;

•fluctuations in exchange and interest rates that could influence revenues and expenses;

•changes in	global	equity	and	fixed income	markets that	could	affect the	return	on invested assets;

•changes	in	the	funding	status	of	our	various	defined	benefit	pension	plans	and	the	impact	of	any	increased	pension	funding	resulting	from	those changes;

•the	 level	 of	 our	 debt limiting financial flexibility	 or increasing	 borrowing costs;

•rating	 agency	 actions that	 could	 affect	 our	 ability to	 borrow funds;

•volatility in	our tax	rate	due to	a	variety	of	different	factors including	U.S.	federal income tax reform;

•changes	in	estimates	or	assumptions	on	our	financial	statements;

•limits	on	our	subsidiaries	to	make	dividend	and	other	payments	to

•the	impact	of	lawsuits	and	other	contingent	liabilities	and	loss	contingencies	arising	from	errors	and	omissions	("E&O")	and	other	claims	against us;

•the	impact	of,	and	potential	challenges	in	complying	with,	legislation	and	regulation	in	the	jurisdictions	in	which	we	operate,	particularly	given	the	global	scope of	our	businesses	and	the	possibility	of	conflicting	regulatory	requirements	across	jurisdictions	in	which	we	do	business;

•the	 impact	 of	 any investigations	 brought	 by regulatory	 authorities in the	 U.S.,	 U.K.,	 and	 other countries;

•the	impact	of	any	inquiries	relating	to	compliance	with	the	U.S.	Foreign	Corrupt	Practices	Act	and	non-U.S.	anti-corruption	laws	and	with	U.S.	and	non-U.S. trade	sanctions	regimes;

•failure	to	protect	intellectual	property	rights	or	allegations	that	we	infringe	on	the	intellectual	property	rights	of others;

•the	effects	of	English	law	on	our	operating	flexibility	and	the	enforcement	of	judgments	against us;

•the failure to retain and attract qualified personnel;

•international risks associated with our global operations;

•the effect of natural or man-made disasters;

•the	potential	of	a	system	or	network	breach	or	disruption	resulting	in	operational	interruption	or	improper	disclosure	of	personal data;

•our ability to develop and implement new technology;

•damage to our reputation among clients,	 markets or third parties;

•the	 actions taken	 by third	 parties that	 perform	 aspects	 of	 our	 business	 operations	 and	 client services;

•the	extent	to	which	we	manage	certain	risks	created	in	connection	with	the	various	services,	including	fiduciary	and	investment	consulting	and	other	advisory services,	among	others,	that	we	currently	provide,	or	will	provide	in	the	future,	to	clients;

•our	ability	to	continue,	and	the	costs	and	risks	associated	with,	growing,	developing	and	integrating	companies	that	we	acquire	or	new	lines	of business;

•changes	 in commercial property and casualty	 markets, commercial premium rates or	 methods of compensation;

•changes in the health care system or our relationships	 with insurance carriers;

•our	 ability to implement initiatives intended to	 yield	 cost	 savings	 and the	 ability to	 achieve those	 cost savings;

•our	risks	and	uncertainties	in	connection	with	the	sale	of	the	Divested	Business;

•our	 ability to realize the	 expected	 benefits from	 our restructuring

# plan.

Any	or	all	of	our	forward-looking	statements	may	turn	out	to	be	inaccurate,	and	there	are	no	guarantees	about	our	performance.	The	factors	identified	above	are	not exhaustive.	Aon	and	its	subsidiaries	operate	in	a	dynamic	business	environment	in	which	new	risks	may	emerge	frequently.	Accordingly,	readers	should	not	place	undue reliance	on	forward-looking	statements,	which	speak	only	as	of	the	dates	on	which	they	are	made.	We	are	under	no	obligation	(and	expressly	disclaim	any	obligation)	to update	or	alter	any	forward-looking	statement	that	we	may	make	from	time	to	time,	whether	as	a	result	of	new	information,	future	events	or	otherwise.	Further information	about	factors	that	could	materially	affect	Aon,	including	our	results	of	operations	and	financial	condition,	is	contained	in	the	"Risk	Factors"	section	in	Part	I, Item	1A	of	this	report.

# Website	Access	to	Reports	and	Other	Information

Our	Annual	Report	on	Form	10-K,	Quarterly	Reports	on	Form	10-Q,	Current	Reports	on	Form	8-K,	and	all	amendments	to	those	reports	are	made	available	free	of charge	through	our	website	(http://www.aon.com)	as	soon	as	reasonably	practicable	after	such	material	is	electronically	filed	with	or	furnished	to	the	SEC.	Also	posted on	our	website	are	 the	charters	for	our	Audit,	Compliance,	Organization	and	Compensation,	Governance/Nominating,	and	Finance	Committees,	our	Governance Guidelines,	and	our	Code	of	Business	Conduct.	Within	the	time	period	required	by	the	SEC	and	the	New	York	Stock	Exchange	("NYSE"),	we	will	post	on	our	website any	amendment	to	or	waiver	of	the	Code	of	Business	Conduct	applicable	to	any	executive	officer	or	director.	The	information	provided	on	our	website	is	not	part	of	this report	and	is	therefore	not	incorporated	herein	by	reference.

# Item	1A.				Risk	Factors

The	risk	factors	set	forth	below	reflect	material	risks	associated	with	existing	and	potential	business	and	contain	"forward-looking	statements"	as	discussed	in	the "Business"	Section	of	Part	I,	Item	1	of	this	report.	Readers	should	consider	them	in	addition	to	the	other	information	contained	in	this	report	as	our	business,	financial condition,	or	results	of	operations	could	be	adversely	affected	if	any	of	these	risks	were	to	actually	occur.

The	following	are	material	risks	related	to	our	businesses	specifically	and	the	industries	in	which	we	operate	generally	that	could	adversely	affect	our	business, financial	condition,	and	results	of	operations	and	cause	our	actual	results	to	differ	materially	from	those	stated	in	the	forward-looking	statements	in	this	document	and elsewhere.

# Business	Risks

An	overall	decline	in	economic	activity	could	have	a	material	adverse	effect	on	the	financial	condition	and	results	of	operations	of	our	business.

The	results	of	our	operations	are	generally	affected	by	the	level	of	business	activity	of	our	clients,	which	in	turn	is	affected	by	the	level	of	economic	activity	in	the industries	and	markets	these	clients	serve.	Economic	downturns,	volatility,	or	uncertainty	in	some	markets	may	cause	reductions	in	technology	and	discretionary spending	by	our	clients,	which	may	result	in	reductions	in	the	growth	of	new	business	or	reductions	in	existing	business.	If	our	clients	become	financially	less	stable, enter	bankruptcy,	liquidate	their	operations	or	consolidate,	our	revenues	and	collectability	of	receivables	could	be	adversely	affected.

The	demand	for	property	and	casualty	insurance	generally	rises	as	the	overall	level	of	economic	activity	increases	and	generally	falls	as	such	activity	decreases, affecting	both	the	commissions	and	fees	generated	by	our	Commercial	Risk	Solutions,	Reinsurance	Solutions,	and	Data	and	Analytic	Services	revenue	lines.	The economic	activity	that	impacts	property	and	casualty	insurance	is	most	closely	correlated	with	employment	levels,	corporate	revenue,	and	asset	values.	Downward fluctuations	in	the	year-over-year	insurance	premiums	charged	by	insurers	to	protect	against	the	same	risk,	referred	to	in	the	industry	as	softening	of	the	insurance market,	could	adversely	affect	these	businesses	as	a	significant	portion	of	the	earnings	are	determined	as	a	percentage	of	premium	charged	to	our	clients.	Insolvencies and	consolidations	associated	with	an	economic	downturn,	especially	insolvencies	in	the	insurance	industry,	could	adversely	affect	our	brokerage	business	through	the loss	of	clients	by	hampering	our	ability	to	place	insurance	and	reinsurance	business.	Also,	error	and	omission	claims	against	us,	which	we	refer	to	as	E&O	claims,	may increase	in	economic	downturns,	also	adversely	affecting	our	business.

# We	face	significant	competitive	pressures.

As	a	global	professional	services	firm,	we	compete	with	global,	national,	regional,	and	local	insurance	companies	that	market	and	service	their	own	products,	other financial	 services	 providers,	 brokers,	 and	 investment	 managers,	 independent	 firms,	 and	 consulting	 organizations	 affiliated	 with	 accounting,	 information	 systems, technology,	and	financial	services	firms.	We	compete	with	respect	to	service,	product	features,	price,	commission	structure,	financial	strength,	ability	to	access	certain insurance	markets,	and	name	recognition.

Our	competitors	may	have	greater	financial,	technical	and	marketing	resources,	larger	customer	bases,	greater	name	recognition,	more	comprehensive	products, stronger	presence	in	certain	geographies,	or	more	established	relationships	with	their

customers	and	suppliers	than	we	have.	In	addition,	new	competitors,	alliances	among	competitors,	or	mergers	of	competitors	could	emerge	and	gain	significant	market share,	and	some	of	our	competitors	may	have	or	may	develop	a	lower	cost	structure,	adopt	more	aggressive	pricing	policies,	or	provide	services	that	gain	greater	market acceptance	than	the	services	that	we	offer	or	develop.	Competitors	may	be	able	to	respond	to	the	need	for	technological	changes	and	innovate	faster,	or	price	their services	more	aggressively.	They	may	also	compete	for	skilled	professionals,	finance	acquisitions,	fund	internal	growth,	and	compete	for	market	share	more	effectively than	we	do.	This	competition	is	intensified	by	an	industry	trend	where	clients	engage	multiple	brokers	to	service	different	portions	of	their	accounts.	If	we	fail	to	respond successfully	to	the	competition	we	face,	our	financial	condition	or	results	of	operations	might	be	adversely	affected.

If	our	clients	or	third	parties	are	not	satisfied	with	our	services,	we	may	face	additional	cost,	loss	of	profit	opportunities,	damage	to	our	reputation,	or	legal	liability.

We	depend,	to	a	large	extent,	on	our	relationships	with	our	clients	and	our	reputation	for	high-quality	advice	and	solutions	focused	on	risk,	retirement,	and	health.	If a	client	is	not	satisfied	with	our	services,	it	could	cause	us	to	incur	additional	costs	and	impair	profitability.	Many	of	our	clients	are	businesses	that	band	together	in industry	groups	or	trade	associations	and	actively	share	information	among	themselves	about	the	quality	of	service	they	receive	from	their	vendors.	Accordingly,	poor service	to	one	client	may	negatively	impact	our	relationships	with	multiple	other	clients.	Moreover,	if	we	fail	to	meet	our	contractual	obligations,	we	could	be	subject	to legal	liability	or	loss	of	client	relationships.

The	nature	of	much	of	our	work	involves	assumptions	and	estimates	concerning	future	events,	the	actual	outcome	of	which	we	cannot	know	with	certainty	in advance.	In	our	investment	consulting	business,	we	may	be	measured	based	on	our	track	record	regarding	judgments	and	advice	on	investments	that	are	susceptible	to influences	unknown	at	the	time	the	advice	was	given.	In	addition,	we	could	make	computational,	software	programming,	or	data	entry	or	management	errors.	A	client may	claim	it	suffered	losses	due	to	reliance	on	our	consulting	advice,	which	poses	risks	of	liability	exposure	and	costs	of	defense	and	increased	insurance	premiums.	In addition,	claims	arising	from	our	professional	services	may	produce	publicity	that	could	hurt	our	reputation	and	business	and	adversely	affect	our	ability	to	retain business	or	secure	new	business.

# Damage	to	our	reputation	could	have	a	material	adverse	effect	on	our	business.

Our	reputation	is	a	key	asset	of	the	Company.	We	advise	our	clients	on	and	provide	services	related	to	a	wide	range	of	subjects	and	our	ability	to	attract	and	retain clients	is	highly	dependent	upon	the	external	perceptions	of	our	level	of	service,	trustworthiness,	business	practices,	financial	condition,	and	other	subjective	qualities. Negative	perceptions	or	publicity	regarding	these	matters	or	others	could	erode	trust	and	confidence	and	damage	our	reputation	among	existing	and	potential	clients, which	could	make	it	difficult	for	us	to	attract	new	clients	and	retain	existing	ones.	Negative	public	opinion	could	also	result	from	actual	or	alleged	conduct	by	us	or	those currently	or	formerly	associated	with	us	in	any	number	of	activities	or	circumstances,	including	third	parties,	the	use	and	protection	of	data	and	systems,	satisfaction	of client	expectations,	and	regulatory	compliance.	Damage	to	our	reputation	could	affect	the	confidence	of	our	clients,	rating	agencies,	regulators,	stockholders,	and	third parties	in	transactions	that	are	important	to	our	business	adversely	effecting	our	business,	financial	condition,	and	operating	results.

Revenues	from	commission	arrangements	may	fluctuate	due	to	many	factors,	including	cyclical	or	permanent	changes	in	the	insurance	and	reinsurance	markets	outside of	our	control.

Revenues	from	commission	arrangements	have	historically	been	affected	by	significant	fluctuations	arising	from	uncertainties	and	changes	in	the	industries	in which	we	operate.	A	significant	portion	of	our	revenue	consists	of	commissions	paid	to	us	out	of	the	premiums	that	insurers	and	reinsurers	charge	our	clients	for coverage.	We	have	no	control	over	premium	rates,	and	our	revenues	and	profitability	are	subject	to	change	to	the	extent	that	premium	rates	fluctuate	or	trend	in	a particular	direction.	The	potential	for	changes	in	premium	rates	is	significant,	due	to	pricing	cyclicality	in	the	commercial	insurance	and	reinsurance	markets.

In	addition	to	movements	in	premium	rates,	our	ability	to	generate	premium-based	commission	revenue	may	be	challenged	by:

•the	growing	availability	of	alternative	methods	for	clients	to	meet	their	risk-protection	needs,	including	a	greater	willingness	on	the	part	of	corporations	to	"self- insure,"	the	use	of	so-called	"captive"	insurers,	and	the	development	of	capital	markets-based	solutions	and	other	alternative	capital	sources	for	traditional insurance	and	reinsurance	needs	that	increase	market	capacity,	increase	competition,	and	put	pressure	on	pricing;

•fluctuation in the need for insurance;

•the	level	of	compensation,	as	a	percentage	of	premium,	that	insurance	carriers	are	willing	to	compensate	brokers	for	placement activity;

•the	growing	desire	of	clients	to	move	away	from	variable	commission	rates	and	instead	compensate	brokers	based	upon	flat	fees,	which	can	negatively	impact us	as	fees	are	not	generally	indexed	for	inflation	and	do	not	automatically	increase	with	premium	as	does	commission-based	compensation;	and

•competition	from	insurers	seeking	to	sell	their	products	directly	to	consumers,	including	online	sales,	without	the	involvement	of	an	insurance broker.

The	profitability	of	our	consulting	engagements	with	clients	may	not	meet	our	expectations	due to	unexpected	costs,	cost	overruns,	early	contract terminations, unrealized	assumptions	used	in	our	contract	bidding	process	or	the	inability	to	maintain	our	prices.

Our	profitability	with	respect	to	consulting	engagements	is	highly	dependent	upon	our	ability	to	control	our	costs	and	improve	our	efficiency.	As	we	adapt	to changes	in	our	business,	adapt	to	the	regulatory	environment,	enter	into	new	engagements,	acquire	additional	businesses,	and	take	on	new	employees	in	new	locations, we	may	not	be	able	to	manage	our	large,	diverse	and	changing	workforce,	control	our	costs,	or	improve	our	efficiency.

Our	profit	margin,	and	therefore	our	profitability,	is	largely	a	function	of	the	rates	we	are	able	to	charge	for	our	services	and	the	staffing	costs	for	our	personnel. Accordingly,	if	we	are	not	able	to	maintain	the	rates	we	charge	for	our	services	or	appropriately	manage	the	staffing	costs	of	our	personnel,	we	may	not	be	able	to sustain	our	profit	margin	and	our	profitability	will	suffer.	The	prices	we	are	able	to	charge	for	our	services	are	affected	by	a	number	of	factors,	including	competitive factors,	the	extent	of	ongoing	clients'	perception	of	our	ability	to	add	value	through	our	services,	and	general	economic	conditions.	If	we	cannot	drive	suitable	cost efficiencies,	our	profit	margins	will	suffer.	Our	cost	efficiencies	may	also	be	impacted	by	factors	such	as	our	ability	to	transition	consultants	from	completed	projects	to new	assignments,	our	ability	to	secure	new	consulting	engagements,	our	ability	to	forecast	demand	for	consulting	services	(and,	consequently,	appropriately	manage	the size	and	location	of	our	workforce),	employee	attrition,	and	the	need	to	devote	time	and	resources	to	training	and	professional	and	business	development.

In	our	investment	consulting	business,	we	advise	or	act	on	behalf	of	clients	regarding	their	investments.	The	results	of	these	investments	are	uncertain	and	subject	to numerous	factors,	some	of	which	are	within	our	control	and	some	which	are	not.	Clients	that	experience	losses	or	lower	than	expected	investment	returns	may	leave	us for	competitors	and/or	assert	claims	against	us.

Our	investment	consulting	business	provides	advice	to	clients	on:	investment	strategy,	which	can	include	advice	on	setting	investment	objectives,	asset	allocation, and	hedging	strategies;	selection	(or	removal)	of	investment	managers;	the	investment	in	different	investment	instruments	and	products;	and	the	selection	of	other investment	service	providers	such	as	custodians	and	transition	managers.	For	some	clients,	we	are	responsible	for	making	decisions	on	these	matters	and	we	may implement	such	decisions	in	a	fiduciary	or	agency	capacity	without	assuming	title	or	custody	over	the	underlying	funds	or	assets	invested.	Asset	classes	may	experience poor	 absolute	 performance	 and	 third	 parties	 we	 recommend	 or	 select,	 such	 as	 investment	 managers,	 may	 underperform	 their	 benchmarks	 due	 to	 poor	 market performance,	negligence,	or	other	reasons,	resulting	in	poor	investment	returns	or	losses.	These	losses	may	be	attributable	in	whole	or	in	part	to	failures	on	our	part	or	to events	entirely	outside	of	our	control,	including	but	not	limited	to	uncertainty	in	financial	markets	due	to	economic,	political,	and	regulatory	conditions.	Regardless	of the	cause,	clients	experiencing	losses	or	clients	that	allege	that	we	overcharge	for	such	fiduciary	services	have	in	the	past	asserted	claims	against	us,	and	we	anticipate future	similar	claims,	which	could	be	for	significant	amounts.	Defending	against	these	claims	can	involve	potentially	significant	costs,	including	legal	defense	costs,	as well	as	cause	substantial	distraction	and	diversion	of	other	resources.	Furthermore,	our	ability	to	limit	our	potential	liability	is	restricted	in	certain	jurisdictions	and	in connection	with	claims	involving	breaches	of	fiduciary	or	agency	duties	or	other	alleged	errors	or	omissions.	Additionally,	clients	experiencing	losses	or	lower	than expected	investment	returns	may	leave	us	for	our	competitors.

# Financial	Risks

We	are	exposed	to	fluctuations	in	currency	exchange	rates	that	could	negatively	impact	our	financial	results	and	cash	flows.

We	face	exposure	to	adverse	movements	in	exchange	rates	of	currencies	other	than	our	reporting	currency,	the	U.S.	dollar,	as	a	significant	portion	of	our	business	is located	 outside	 of	 the	 U.S.	 These	 exposures	 may	 change	 over	 time,	 and	 they	 could	 have	 a	 material	 adverse	 impact	 on	 our	 financial	 results	 and	 cash	 flows. Approximately	57%	of	our	consolidated	revenue	is	non-U.S.,	attributed	on	the	basis	of	where	the	services	are	performed,	and	the	exposures	created	can	have	significant currency	volatility.	These	currency	exchange	fluctuations	create	risk	in	both	the	translation	of	the	financial	results	of	our	global	subsidiaries	into	U.S.	dollars	for	our consolidated	financial	statements,	as	well	as	in	those	of	our	operations	that	receive	revenue	and	incur	expenses	other	than	in	their	respective	local	currencies,	which	can reduce	the	profitability	of	our	operations	based	on	the	direction	the	respective	currencies'	exchange	rates	move.	A	decrease	in	the	value	of	certain	currencies	relative	to other	currencies	could	place	us	at	a	competitive	disadvantage	compared	to	our	competitors	that	benefit	to	a	greater	degree	from	a	specific	exchange	rate	move	and	can, as	a	result,	deliver	services	at	a	lower	cost	or	receive	greater	revenues	from	such	a	transaction.	Although	we	use	various	derivative	financial	instruments	to	help	protect against	adverse	foreign	exchange	rate	fluctuations,	we	cannot	eliminate	such	risks,	and,	as	a	result,	changes	in	exchange	rates	may	adversely	affect	our	results.	For example,	the	strengthening	of	the	value	of	the	U.S.	dollar	versus	other	currencies	might	adversely	affect	the	value	of	our	products	and	services	when	translated	to	U.S. dollar,	even	if	the	value	of	such	products	and	services	has	not	changed	in	their	original	currency.

Changes	in	interest	rates	and	deterioration	of	credit	quality	could	reduce	the	value	of	our	cash	balances	and	investment	portfolios	and	adversely	affect	our	financial condition	or	results.

Operating	funds	available	for	corporate	use	were	$828	million	at	December	31,	2018	and	are	reported	in	Cash	and	cash	equivalents	and	Short-term	investments. Funds	held	on	behalf	of	clients	and	insurers	were	$3.9	billion	at	December	31,	2018	and	are	reported	in	Fiduciary	assets.	We	also	carry	an	investment	portfolio	of	other long-term	investments.	As	of	December	31,	2018,	these	long-term	investments	had	a	carrying	value	of	$54	million.	Adverse	changes	in	interest	rates,	performance,	and counterparty	credit	quality,	including	default,	could	reduce	the	value	of	these	funds	and	investments,	thereby	adversely	affecting	our	financial	condition	or	results.	We may	experience	reduced	investment	earnings	on	our	cash	and	short-term	investments	of	fiduciary	and	operating	funds	if	the	yields	on	investments	deemed	to	be	low	risk remain	at	or	near	their	current	low	levels,	or	if	negative	yields	on	deposits	or	investments	are	experienced,	as	we	have	experienced	in	Japan	and	certain	jurisdictions	in the	European	Union.	On	the	other	hand,	higher	interest	rates	could	result	in	a	higher	discount	rate	used	by	investors	to	value	our	future	cash	flows	thereby	resulting	in	a lower	valuation	of	the	Company.	In	addition,	during	times	of	stress	in	the	banking	industry,	counterparty	risk	can	quickly	escalate,	potentially	resulting	in	substantial losses	for	us	as	a	result	of	our	cash	or	other	investments	with	such	counterparties,	as	well	as	substantial	losses	for	our	clients	and	the	insurance	companies	with	which	we work.

Our	pension	obligations	and	value	of	our	pension	assets	could	adversely	affect	our	shareholders'	equity,	net	income,	cash	flow	and	liquidity.

To	the	extent	that	the	pension	obligations	associated	with	our	pension	plans	continue	to	exceed	the	fair	value	of	the	assets	supporting	those	obligations,	our	financial position	and	results	of	operations	may	be	adversely	affected.	In	particular,	lower	interest	rates	and	investment	returns	could	result	in	the	present	value	of	plan	liabilities increasing	at	a	greater	rate	than	the	value	of	plan	assets,	resulting	in	higher	unfunded	positions	in	our	pension	plans.	In	addition,	the	periodic	revision	of	pension assumptions	or	variances	of	actual	results	from	our	assumptions	can	materially	change	the	present	value	of	expected	future	benefits,	and	therefore	the	funded	status	of the	plans	and	resulting	net	periodic	pension	expense.	As	a	result,	we	may	experience	future	changes	in	the	funded	status	of	our	plans	that	could	require	us	to	make additional	cash	contributions	beyond	those	that	have	been	estimated	and	which	could	adversely	affect	shareholders'	equity,	net	income,	cash	flow	and	liquidity.

Our	worldwide	pension	plans	are	significant,	and	therefore	our	pension	contributions	and	expense	are	sensitive	to	various	market,	demographic,	and	other	factors. These	factors	include	equity	and	bond	market	returns,	fair	value	of	pension	assets,	the	assumed	interest	rates	we	use	to	discount	our	pension	liabilities,	foreign	exchange rates,	 rates	 of	 inflation,	 mortality	 assumptions,	 potential	 regulatory	 and	 legal	 changes	 or	 developments	 and	 counterparty	 exposure	 from	 various	 investments	 and derivative	contracts,	including	annuities.	Variations	or	developments	in	connection	with	any	of	these	factors	could	cause	significant	changes	to	our	financial	position	and results	of	operations	from	year	to	year.	In	addition,	contributions	are	generally	based	on	statutory	requirements	and	local	funding	practices,	which	may	differ	from measurements	under	U.S.	Generally	Accepted	Accounting	Principles	("U.S.	GAAP").

# We	have	debt	outstanding	that	could	adversely	affect	our	financial	flexibility.

As	of	December	31,	2018,	we	had	total	consolidated	debt	outstanding	of	approximately	$6.2	billion.	The	level	of	debt	outstanding	could	adversely	affect	our financial	flexibility	by	reducing	our	ability	to	use	cash	from	operations	for	other	purposes,	including	working	capital,	dividends	to	shareholders,	share	repurchases, acquisitions,	capital	expenditures	and	general	corporate	purposes.	We	also	are	subject	to	risks	that,	at	the	time	any	of	our	outstanding	debt	matures,	we	will	not	be	able	to retire	or	refinance	the	debt	on	terms	that	are	acceptable	to	us,	or	at	all.

As	of	December	31,	2018,	we	had	two	committed	credit	facilities	outstanding.	Each	of	these	facilities	is	intended	to	support	our	commercial	paper	obligations	and our	general	working	capital	needs.	In	addition,	each	of	these	facilities	included	customary	representations,	warranties,	and	covenants,	including	financial	covenants	that require	us	to	maintain	specified	ratios	of	adjusted	consolidated	EBITDA	to	consolidated	interest	expense	and	consolidated	debt	to	adjusted	consolidated	EBITDA,	tested quarterly.

A	substantial	portion	of	our	outstanding	debt,	including	certain	intercompany	debt	obligations,	contains	financial	and	other	covenants.	The	terms	of	these	covenants may	limit	our	ability	to	obtain,	or	increase	the	costs	of	obtaining,	additional	financing	to	fund	working	capital,	capital	expenditures,	acquisitions,	or	general	corporate requirements.	This	in	turn	may	have	the	impact	of	reducing	our	flexibility	to	respond	to	changing	business	and	economic	conditions,	thereby	placing	us	at	a	relative disadvantage	 compared	 to	 competitors	 that	 have	 less	 indebtedness,	 or	 fewer	 or	 less	 onerous	 covenants	 associated	 with	 such	 indebtedness,	 and	 making	 us	 more vulnerable	to	general	adverse	economic	and	industry	conditions.

If	we	cannot	service	our	indebtedness,	we	may	have	to	take	actions	such	as	selling	assets,	seeking	additional	equity,	or	reducing	or	delaying	capital	expenditures, strategic	acquisitions,	investments,	and	alliances,	any	of	which	could	impede	the	implementation	of	our	business	strategy	or	prevent	us	from	entering	into	transactions that	would	otherwise	benefit	our	business.	Additionally,	we	may	not	be	able	to	effect	such	actions	or	refinance	any	of	our	debt,	if	necessary,	on	commercially	reasonable terms,	or	at	all.

A	decline	in	the	credit	ratings	of	our	senior	debt	and	commercial	paper	may	adversely	affect	our	borrowing	costs,	access	to	capital,	and	financial	flexibility.

A	downgrade	in	the	credit	ratings	of	our	senior	debt	and	commercial	paper	could	increase	our	borrowing	costs,	reduce	or	eliminate	our	access	to	capital,	reduce	our financial	flexibility,	and	limit	our	ability	to	implement	on	corporate	strategy.	Our	senior	debt	ratings	at	December	31,	2018	were	A-	with	a	stable	outlook	(Standard	& Poor's,	or	"S&P"),	BBB+	with	a	stable	outlook	(Fitch,	Inc.,	or	"Fitch"),	and	Baa2	with	a	stable	outlook	(Moody's	Investor	Services,	or	"Moody's").	Our	commercial paper	ratings	were	A-2	(S&P),	F-2	(Fitch)	and	P-2	(Moody's).

Real	or	anticipated	changes	in	our	credit	ratings	will	generally	affect	any	trading	market	for,	or	trading	value	of,	our	securities.	Such	changes	could	result	from	any number	of	factors,	including	the	modification	by	a	credit	rating	agency	of	the	criteria	or	methodology	it	applies	to	particular	issuers,	a	change	in	the	agency's	view	of	us or	our	industry,	or	as	a	consequence	of	actions	we	take	to	implement	our	corporate	strategies.	A	change	in	our	credit	rating	could	adversely	limit	our	access	to	capital and	our	competitive	position.

# U.S.	federal	income	tax	reform	could	create	uncertainty	and	adversely	affect	our	business	and	financial	condition.

On	December	22,	2017,	U.S.	federal	tax	legislation,	commonly	referred	to	as	the	Tax	Cuts	and	Jobs	Act	(the	"Tax	Reform	Act"),	was	signed	into	law,	significantly changing	 the	U.S.	Internal	Revenue	Code.	These	changes	 include,	among	other	 things,	 lowering	 the	corporate	 income	 tax	rate,	subjecting	certain	future	foreign subsidiary	earnings,	whether	or	not	distributed,	to	U.S.	tax	under	a	Global	Intangible	Low-Taxed	Income	provision,	imposing	a	new	alternative	"Base	Erosion	and	Anti- Abuse	Tax"	on	U.S.	corporations	that	limits	deductions	for	certain	deductible	amounts	payable	to	foreign	affiliates,	imposing	significant	additional	limitations	on	the deductibility	of	interest	payable	to	related	and	unrelated	lenders,	further	limiting	deductible	executive	compensation,	and	imposing	a	one-time	repatriation	tax	on deemed	repatriated	earnings	of	foreign	subsidiaries	accumulations	through	the	end	of	2017.	The	new	provisions	have	been	the	subject	of	proposed	regulations	and	other guidance	that,	if	and	when	issued	in	final	form,	could	materially	affect	the	application	of	the	new	statutory	provisions.	In	many	cases,	the	proposed	regulations	and	other guidance	proposed	to	apply	retroactively	to	the	date	of	enactment	of	the	Tax	Reform	Act.	The	government	could	also	further	modify	the	rules	when	they	are	issued	in final	form.	We	continue	to	analyze	how	the	Tax	Reform	Act,	and	any	regulations	or	other	governmental	action	with	respect	thereto,	may	impact	our	business	and	results of	operations.		The	changes	effected	pursuant	to	the	Tax	Reform	Act,	and	the	regulations	or	other	governmental	action	thereunder,	may	have	an	adverse	or	volatile	effect on	our	tax	rate	in	fiscal	years	2019	and	beyond,	thereby	affecting	our	results	of	operations.	Additionally,	the	resulting	uncertainty	with	respect	to	the	interpretation	and application	of	the	new	provisions,	and	the	risk	that	regulations	or	other	governmental	guidance,	including	revisions	to	any	such	regulations	or	other	governmental	action that	may	change	the	application	of	the	new	statutory	provisions,	may	affect	our	assessment	of	the	effect	of	the	Tax	Reform	Act	on	our	business	and	operations	as	we continue	to	analyze	it.

Our	global	effective	tax	rate	is	subject	to	a	variety	of	different	factors,	which	could	create	volatility	in	that	tax	rate,	expose	us	to	greater	than	anticipated	tax	liabilities	or cause	us	to	adjust	previously	recognized	tax	assets	and	liabilities.

We	are	subject	to	income	taxes	in	the	U.K.,	U.S.	and	many	other	jurisdictions.	As	a	result,	our	global	effective	tax	rate	from	period	to	period	can	be	affected	by many	factors,	including	changes	in	tax	legislation	or	regulations,	such	as	the	enactment	of	the	U.S.	Tax	Reform	Act	detailed	above,	the	continuing	development	of regulations	and	other	governmental	action	that	affect	the	application	of	such	legislation,	our	global	mix	of	earnings,	the	use	of	global	funding	structures,	the	tax characteristics	of	our	 income,	 the	effect	of	complying	with	 transfer	pricing	requirements	under	 laws	of	many	different	countries	on	our	revenues	and	costs,	 the consequences	of	acquisitions	and	dispositions	of	businesses	and	business	segments,	and	the	portion	of	the	income	of	non-U.S.	subsidiaries	that	may	be	subject	to	U.S. tax,	or	the	portion	of	the	income	of	non-U.K	subsidiaries	that	may	be	subject	to	U.K.	tax,	whether	or	not	distributed	to	the	respective	U.S.	or	U.K.	shareholders.	In addition,	we	could	be	subject	to	increased	taxation	as	a	result	of	changes	in	eligibility	for	the	benefits	of	current	income	tax	treaties	between	and	among	the	U.K.,	the U.S.,	and	other	countries,	including	any	future	amendments	to	the	current	income	tax	treaties	between	the	U.K.	and	other	jurisdictions	(including	the	U.S.),	or	any	new statutory	or	regulatory	provisions	that	might	limit	our	ability	to	take	advantage	of	any	such	treaties.	Significant	judgment	is	required	in	determining	our	worldwide provision	for	income	taxes,	and	our	determination	of	the	amount	of	our	tax	liability	is	always	subject	to	review	by	applicable	tax	authorities.	Our	actual	global	tax	rate may	vary	from	our	expectation	and	that	variance	may	be	material.

We	are	subject	to	tax	audits	conducted	by	U.S.,	U.K.,	and	other	tax	authorities,	and	the	resolution	of	such	audits	could	impact	our	tax	rate	in	future	periods,	as would	any	reclassification	or	other	changes	(such	as	 those	 in	applicable	accounting	rules)	 that	 increases	 the	amounts	we	have	provided	for	 income	 taxes	 in	our consolidated	financial	statements.	There	can	be	no	assurance	that	we	would	be	successful	in	attempting	to	mitigate	the	adverse	impacts	resulting	from	any	changes	in law,	audits	and	other	matters.	Our	inability	to	mitigate	the	negative	consequences	of	any	changes	in	the	law,	audits	and	other	matters	could	cause	our	global	tax	rate	to increase,	our	use	of	cash	to	increase	and	our	financial	condition	and	results	of	operations	to	suffer.

# Changes	in	our	accounting	estimates	and	assumptions	could	negatively	affect	our	financial	position	and	results	of	operations.

We	prepare	our	consolidated	financial	statements	in	accordance	with	U.S.	GAAP.	These	accounting	principles	require	us	to	make	estimates	and	assumptions	that affect	the	reported	amounts	of	assets	and	liabilities,	and	the	disclosure	of	contingent	assets	and	liabilities	at	the	date	of	our	financial	statements.	We	are	also	required	to make	certain	judgments	that	affect	the	reported	amounts	of	revenues	and	expenses	during	each	reporting	period.	We	periodically	evaluate	our	estimates	and	assumptions including,	but	not	limited	to,	those	relating	to	revenue	recognition,	restructuring,	pensions,	recoverability	of	assets	including	customer	receivables,	valuation	of	goodwill and	intangibles,	contingencies,	share-based	payments,	and	income	taxes.	We	base	our	estimates	on	historical	experience	and	various	assumptions	that	we	believe	to	be reasonable	based	on	specific	circumstances.	These	assumptions	and	estimates	involve	the	exercise	of	judgment	and	discretion,	which	may	evolve	over	time	in	light	of operational	experience,	regulatory	direction,	developments	or	changes	in	accounting	principles	or	standards,	and	other	factors.	Actual	results	could	differ	from	these estimates,	 or	 changes	 in	 assumptions,	 estimates,	 policies,	 or	 developments	 in	 the	 business	 may	 change	 our	 initial	 estimates,	 which	 could	 materially	 affect	 the Consolidated	Statements	of	Income,	Comprehensive	Income,	Financial	Position,	Shareholders'	Equity,	and	Cash	Flows.

We	may	be	required	to	record	goodwill	or	other	long-lived	asset	impairment	charges,	which	could	result	in	a	significant	charge	to	earnings.

Under	U.S.	GAAP,	we	review	our	long-lived	assets	for	impairment	when	events	or	changes	in	circumstances	indicate	the	carrying	value	may	not	be	recoverable. Goodwill	is	assessed	for	impairment	at	least	annually.	Factors	that	may	be	considered	in	assessing	whether	goodwill	or	other	long-lived	assets	may	not	be	recoverable include	a	decline	in	our	share	price	or	market	capitalization,	reduced	estimates	of	future	cash	flows	and	slower	growth	rates	in	our	industry.	We	may	experience unforeseen	circumstances	that	adversely	affect	the	value	of	our	goodwill	or	other	long-lived	assets	and	trigger	an	evaluation	of	the	recoverability	of	the	recorded goodwill	 and	 other	 long-lied	 intangible	 assets.	 Future	 goodwill	 or	 other	 long-lived	 asset	 impairment	 charges	 could	 materially	 impact	 our	 consolidated	 financial statements.

We	are	a	holding	company	and,	therefore,	may	not	be	able	to	receive	dividends	or	other	payments	in	needed	amounts	from	our	subsidiaries.

The	Company	is	organized	as	a	holding	company,	a	legal	entity	separate	and	distinct	from	our	operating	entities.	As	a	holding	company	without	significant operations	of	its	own,	our	principal	assets	are	the	shares	of	capital	stock	of	our	subsidiaries.	We	rely	on	dividends,	interest,	and	other	payments	from	these	subsidiaries to	meet	our	obligations	for	paying	principal	and	interest	on	outstanding	debt,	paying	dividends	to	shareholders,	repurchasing	ordinary	shares,	and	corporate	expenses. Certain	of	our	subsidiaries	are	subject	 to	regulatory	requirements	of	 the	 jurisdictions	 in	which	 they	operate	or	other	restrictions	 that	may	 limit	 the	amounts	 that subsidiaries	can	pay	in	dividends	or	other	payments	to	us.	No	assurance	can	be	given	that	there	will	not	be	further	changes	in	law,	regulatory	actions,	or	other circumstances	that	could	restrict	the	ability	of	our	subsidiaries	to	pay	dividends	or	otherwise	make	payments	to	us.	Furthermore,	no	assurance	can	be	given	that	our subsidiaries	may	be	able	to	make	timely	payments	to	us	in	order	for	us	to	meet	our	obligations.

# Legal	and	Regulatory	Risks

We	are	subject	to	E&O	claims	against	us	as	well	as	other	contingencies	and	legal	proceedings,	some	of	which,	if	determined	unfavorably	to	us,	could	have	a	material adverse	effect	on	the	financial	condition	or	results	of	operations	of	a	business	line	or	the	Company	as	a	whole.

We	assist	our	clients	with	various	matters,	 including	placing	 insurance	and	reinsurance	coverage	and	handling	related	claims,	consulting	on	various	human resources	matters,	and	providing	actuarial,	investment	consulting,	and	asset	management	services.	E&O	claims	against	us	may	allege	our	potential	liability	for	damages arising	from	these	services.	E&O	claims	could	include,	for	example,	the	failure	of	our	employees	or	sub-agents,	whether	negligently	or	intentionally,	to	place	coverage correctly	or	notify	carriers	of	claims	on	behalf	of	clients,	to	provide	insurance	carriers	with	complete	and	accurate	information	relating	to	the	risks	being	insured,	or	the failure	to	give	error-free	consulting	or	investment	advice.	It	is	not	always	possible	to	prevent	and	detect	E&O,	and	the	precautions	we	take	may	not	be	effective	in	all cases.	In	addition,	we	are	subject	to	other	types	of	claims,	litigation,	and	proceedings	in	the	ordinary	course	of	business,	which	along	with	E&O	claims,	may	seek damages,	including	punitive	damages,	in	amounts	that	could,	if	awarded,	have	a	material	adverse	impact	on	the	Company's	financial	position,	earnings,	and	cash	flows. In	addition	to	potential	liability	for	monetary	damages,	such	claims	or	outcomes	could	harm	our	reputation	or	divert	management	resources	away	from	operating	our business.

We	have	historically	purchased,	and	intend	to	continue	to	purchase,	insurance	to	cover	E&O	claims	and	other	insurance	to	provide	protection	against	certain	losses that	 arise	 in	 such	 matters.	 However,	 we	 have	 exhausted	 or	 materially	 depleted	 our	 coverage	 under	 some	 of	 the	 policies	 that	 protect	 us	 for	 certain	 years	 and, consequently,	are	self-insured	or	materially	self-insured	for	some	historical	claims.	Additionally,	parts	or	all	of	an	E&O	claim	could	fall	within	insurance	deductibles, self-insured	retentions,	or	policy	exclusions.	Accruals	for	these	exposures,	and	related	insurance	receivables,	when	applicable,	have	been	provided	to	the

extent	that	losses	are	deemed	probable	and	are	reasonably	estimable.	These	accruals	and	receivables	are	adjusted	from	time	to	time	as	developments	warrant	and	may also	be	adversely	affected	by	disputes	we	may	have	with	our	insurers	over	coverage.	Amounts	related	to	settlement	provisions	are	recorded	in	Other	general	expenses	in the	Consolidated	Statements	of	Income.	Discussion	of	some	of	these	claims,	lawsuits,	and	proceedings	are	contained	in	the	Notes	to	Consolidated	Financial	Statements.

In	addition,	we	provide	a	variety	of	guarantees	and	indemnifications	to	our	customers	and	others.	In	the	event	of	a	default,	Aon's	potential	exposure	is	equal	to	the amount	of	the	guarantee	or	indemnification.

The	ultimate	outcome	of	claims,	lawsuits,	proceedings,	guarantees	and	indemnifications	cannot	be	ascertained,	and	liabilities	in	indeterminate	amounts	may	be imposed	on	us.	It	is	possible	that	future	results	of	operations	or	cash	flows	for	any	particular	quarterly	or	annual	period	could	be	materially	affected	by	an	unfavorable resolution	of	these	matters.

# Our	businesses	are	subject	to	extensive	governmental	regulation,	which	could	reduce	our	profitability,	limit	our	growth,	or	increase	competition.

Our	businesses	are	subject	to	extensive	legal	and	regulatory	oversight	throughout	the	world,	including	the	U.K.	Companies	Act	and	the	rules	and	regulations promulgated	by	the	FCA,	the	U.S.	securities	laws,	rules,	and	regulations,	and	a	variety	of	other	laws,	rules,	and	regulations	addressing,	among	other	things,	licensing, data	privacy	and	protection,	trade	restriction	and	export	controls,	anti-money	laundering,	wage-and-hour	standards,	employment	and	labor	relations,	anti-competition, anti-corruption,	currency,	reserves,	government	contracting,	and	the	amount	of	local	investment	with	respect	to	our	operations	in	certain	countries.	This	legal	and regulatory	oversight	could	reduce	our	profitability	or	limit	our	growth	by:	increasing	the	costs	of	legal	and	regulatory	compliance;	limiting	or	restricting	the	products	or services	we	sell,	the	markets	we	serve	or	enter,	the	methods	by	which	we	sell	our	products	and	services,	the	prices	we	can	charge	for	our	services,	or	the	form	of compensation	we	can	accept	from	our	clients,	carriers,	and	third	parties;	or	by	subjecting	our	businesses	to	the	possibility	of	legal	and	regulatory	actions,	proceedings,	or fines.

The	global	nature	of	our	operations	increases	the	complexity	and	cost	of	compliance	with	laws	and	regulations	adding	to	our	cost	of	doing	business.	In	addition, many	of	these	laws	and	regulations	may	have	differing	or	conflicting	legal	standards	across	jurisdictions,	increasing	the	complexity	and	cost	of	compliance.	In	emerging markets	and	other	jurisdictions	with	less	developed	legal	systems,	local	laws	and	regulations	may	not	be	established	with	sufficiently	clear	and	reliable	guidance	to provide	us	adequate	assurance	that	we	are	operating	our	business	in	a	compliant	manner	with	all	required	licenses	or	that	our	rights	are	otherwise	protected.	In	addition, certain	laws	and	regulations,	such	as	the	Foreign	Corrupt	Practices	Act	("FCPA")	and	the	Foreign	Account	Tax	Compliance	provisions	of	the	Hiring	Incentives	to Restore	Employment	Act	("FATCA")	in	the	U.S.,	and	the	Bribery	Act	of	2010	("U.K.	Bribery	Act")	in	the	U.K.,	impact	our	operations	outside	of	the	legislating	country by	imposing	requirements	for	the	conduct	of	overseas	operations,	and	in	several	cases,	requiring	compliance	by	foreign	subsidiaries.

In	addition	to	the	complexity	of	the	laws	and	regulations	themselves,	the	development	of	new	laws	and	regulations	or	changes	in	application	or	interpretation	of current	 laws	and	regulations	also	 increases	our	 legal	and	regulatory	compliance	complexity.	Additionally,	our	acquisitions	of	new	businesses	and	our	continued operational	changes	and	entry	into	new	jurisdictions	and	new	service	offerings	increases	our	legal	and	regulatory	compliance	complexity,	as	well	as	the	type	of governmental	oversight	to	which	we	may	be	subject.	Changes	in	laws	and	regulations	could	mandate	significant	and	costly	changes	to	the	way	we	implement	our services	and	solutions,	could	impose	additional	licensure	requirements	or	costs	to	our	operations	and	services,	or	even	cause	us	to	cease	offering	certain	services	or solutions.	Furthermore,	as	we	enter	new	jurisdictions	or	businesses	and	further	develop	and	expand	our	services,	we	may	become	subject	to	additional	types	of	laws	and policies	and	governmental	oversight	and	supervision,	such	as	those	applicable	to	the	financial	lending	or	other	service	institutions.	New	regulatory	developments	that could	result	in	changes	that	adversely	affect	us	or	cause	us	to	change	our	business	or	operations	include:	additional	requirements	respecting	data	privacy,	data	security, and	data	usage	in	jurisdictions	in	which	we	operate	that	may	increase	our	costs	of	compliance	and	potentially	reduce	the	manner	in	which	we	can	use	data;	additional changes	in	tax	regulations	in	the	jurisdictions	in	which	we	operate;	changes	in	accounting	standards;	regulatory	actions	or	changes	that	require	us	to	change	our compensation	model;	or	additional	regulations	promulgated	by	the	FCA	in	the	U.K.,	or	other	regulatory	bodies	in	jurisdictions	in	which	we	operate.

In	all	jurisdictions,	the	applicable	laws	and	regulations	are	subject	to	amendment	or	interpretation	by	regulatory	authorities.	Generally,	such	authorities	are	vested with	relatively	broad	discretion	to	grant,	renew,	and	revoke	licenses	and	approvals	and	to	implement	regulations.	Accordingly,	we	may	have	a	license	revoked	or	be unable	to	obtain	new	licenses	and	therefore	be	precluded	or	temporarily	suspended	from	carrying	on	or	developing	some	or	all	of	our	activities	or	otherwise	fined	or penalized	in	a	given	jurisdiction.	No	assurances	can	be	given	that	our	business	can	further	develop	or	continue	to	be	conducted	in	any	given	jurisdiction	in	the	future	as	it has	been	conducted	in	the	past.

Changes	in	the	regulatory	scheme,	or	even	changes	in	how	existing	regulations	are	interpreted,	could	have	an	adverse	impact	on	our	results	of	operations	by	limiting revenue	streams	or	increasing	costs	of	compliance.	For	instance,	The	General	Data	Protection	Regulation	("GDPR"),	which	became	effective	in	May	2018,	created	a range	of	new	compliance	obligations,	increased	financial	penalties	for	non-compliance,	and	extended	the	scope	of	the	European	Union	data	protection	law	to	all companies	processing	data

of	European	Union	residents,	wherever	the	company's	location.	We	have	incurred	substantial	operational	costs	to	bring	our	practices	into	compliance	with	GDPR	and where	other	jurisdictions	enact	privacy	and	data	protection	regulations,	we	will	incur	further	expenses	to	bring	our	practices	in	compliance	with	those	regulations,	which may	differ	from	GDPR.

Our	business'	regulatory	oversight	also	includes	licensing	of	insurance	brokers	and	agents,	managing	general	agency	or	general	underwriting	operations,	and	the regulation	of	the	handling	and	investment	of	client	funds	held	in	a	fiduciary	capacity.	Our	continuing	ability	to	provide	insurance	broking	in	the	jurisdictions	in	which	we operate	depends	on	our	compliance	with	the	rules	and	regulations	promulgated	by	the	regulatory	authorities	in	each	of	these	jurisdictions.	Also,	we	can	be	affected indirectly	by	the	governmental	regulation	and	supervision	of	insurance	companies.	For	instance,	if	we	are	providing	or	managing	general	underwriting	services	for	an insurer,	we	may	have	to	contend	with	regulations	affecting	our	client.

Services	provided	in	our	Health	Solutions	and	Retirement	Solutions	revenue	lines	are	also	the	subject	of	ever-evolving	government	regulation,	either	because	the services	provided	to	our	clients	are	regulated	directly	or	because	third	parties	upon	whom	we	rely	to	provide	services	to	clients	are	regulated,	thereby	indirectly	affecting the	manner	in	which	we	provide	services	to	those	clients.	In	particular,	our	health	care	exchange	business	depends	upon	the	private	sector	of	the	U.S.	insurance	system and	its	role	in	financing	health	care	delivery,	and	insurance	carriers'	use	and	payment	of	commissions	to	agents,	brokers,	and	other	organizations	to	market	and	sell individual	and	family	health	insurance	products	and	plans.	Uncertainty	regarding,	or	any	changes	to,	state	or	federal	law,	or	the	interpretation	of	such	law	by	applicable regulatory	agencies,	including	the	effects	of	health	care	reform	by	the	U.S.	government,	could	delay	client	adoption	of	our	health	care	exchanges,	impair	our	ability	to retain	clients	who	have	adopted	our	health	care	exchanges,	or	cause	insurance	carriers	to	alter	or	eliminate	the	products	and	plans	that	they	offer	or	attempt	to	move members	into	new	products	or	plans	for	which	we	receive	lower	commissions.	In	addition,	changes	in	laws,	government	regulations,	or	the	way	those	regulations	are interpreted	in	the	jurisdictions	in	which	we	operate	could	affect	the	viability,	value,	use,	or	delivery	of	benefits	and	human	resources	programs,	including	changes	in regulations	relating	to	health	and	welfare	plans	(such	as	medical),	defined	contribution	plans	(such	as	401(k)),	or	defined	benefit	plans	(such	as	pension),	may	adversely affect	the	demand	for,	or	profitability	of,	our	services.

If	we	violate	 the	 laws	and	regulations	 to	which	we	are	subject,	we	could	be	subject	 to	fines,	penalties,	or	criminal	sanctions	and	could	be	prohibited	from conducting	business	in	one	or	more	countries.	There	can	be	no	assurance	that	our	employees,	contractors,	or	agents	will	not	violate	these	laws	and	regulations,	causing an	adverse	effect	on	our	operations	and	financial	condition.

Heightened	regulatory	oversight	and	scrutiny	may	lead	to	additional	regulatory	investigations,	increased	government	involvement,	or	enforcement	actions.	For instance,	increased	scrutiny	by	competition	authorities	may	increase	our	costs	of	doing	business	or	force	us	to	change	the	way	we	conduct	business	or	refrain	from	or otherwise	alter	the	way	we	engage	in	certain	activities.	Additionally,	we	operate	in	many	different	business	lines,	which	may	occasionally	intersect	with	each	other,	such as	placing	both	insurance	and	reinsurance	or	providing	both	investment	consultancy	and	fiduciary	management	services.			If	we	fail	to	control	possible	resulting	conflicts of	interest,	we	could	be	subject	to	civil	litigation,	fines,	penalties,	and	criminal	sanctions	and	could	be	prohibited	from	participating	in	one	or	more	lines	of	business.		As regulators	and	other	government	agencies	continue	to	examine	our	operations,	there	is	no	assurance	that	consent	orders	or	other	enforcement	actions	will	not	be	issued by	them	in	the	future.	These	and	other	initiatives	from	national,	state,	and	local	officials	may	subject	us	to	judgments,	settlements,	fines,	or	penalties,	or	cause	us	to	be required	to	restructure	or	divest	operations	and	activities,	all	of	which	could	lead	to	reputational	issues,	higher	operational	costs,	business	disruption	or	loss,	thereby adversely	affecting	our	business,	financial	condition,	or	operating	results.

Failure	to	protect	our	intellectual	property	rights,	or	allegations	that	we	have	infringed	on	the	intellectual	property	rights	of	others,	could	harm	our	reputation,	ability to	compete	effectively,	and	financial	condition.

To	protect	our	 intellectual	property	rights,	we	rely	on	a	combination	of	 trademark	 laws,	copyright	 laws,	patent	 laws,	 trade	secret	protection,	confidentiality agreements,	and	other	contractual	arrangements	with	our	affiliates,	employees,	clients,	strategic	partners,	and	others.	However,	the	protective	steps	that	we	take	may	be inadequate	to	deter	misappropriation	of	our	proprietary	information.	In	addition,	we	may	be	unable	to	detect	the	unauthorized	use	of,	or	take	appropriate	steps	to	enforce, our	intellectual	property	rights.	Further,	effective	trademark,	copyright,	patent,	and	trade	secret	protection	may	not	be	available	in	every	country	in	which	we	offer	our services	or	competitors	may	develop	products	similar	to	our	products	that	do	not	conflict	with	our	related	intellectual	property	rights.	Failure	to	protect	our	intellectual property	adequately	could	harm	our	reputation	and	affect	our	ability	to	compete	effectively.

In	 addition,	 to	 protect	 or	 enforce	 our	 intellectual	 property	 rights,	 we	 may	 initiate	 litigation	 against	 third	 parties,	 such	 as	 infringement	 suits	 or	 interference proceedings.		Third	parties	may	assert	intellectual	property	rights	claims	against	us,	which	may	be	costly	to	defend,	could	require	the	payment	of	damages,	and	could limit	our	ability	to	use	or	offer	certain	technologies,	products,	or	other	intellectual	property.	Any	intellectual	property	claims,	with	or	without	merit,	could	be	expensive, take	significant	time	and	divert	management's	attention	from	other	business	concerns.	Successful	challenges	against	us	could	require	us	to	modify	or	discontinue	our	use of	technology	or	business	processes	where	such	use	is	found	to	infringe	or	violate	the	rights	of	others,	or

require	us	to	purchase	licenses	from	third	parties,	any	of	which	could	adversely	affect	our	business,	financial	condition,	and	operating	results.

We	have	less	flexibility	as	a	public	limited	company	incorporated	under	the	laws	of	England	and	Wales	with	respect	to	certain	aspects	of	capital	management.

English	law	imposes	additional	restrictions	on	certain	corporate	actions.	For	example,	English	law	provides	that	a	board	of	directors	may	only	allot	securities	with the	prior	authorization	of	shareholders,	with	such	authorization	specifying	a	maximum	amount	of	shares	that	may	be	allotted	under	it,	and	lasting	for	a	maximum	period of	five	years,	each	as	specified	in	the	articles	of	association	or	relevant	shareholder	resolution.	The	current	authorization	is	effective	until	the	earlier	of	our	next	annual general	meeting	or	August	31,	2019.	This	authorization	will	need	to	be	renewed	by	our	shareholders	periodically	and	we	intend	to	renew	this	authorization	at	each annual	general	meeting.

English	law	also	generally	provides	shareholders	with	preemptive	rights	when	new	shares	are	issued	for	cash;	however,	it	is	possible	for	the	articles	of	association, or	shareholders	in	general	meeting,	to	exclude	preemptive	rights.	Such	an	exclusion	of	preemptive	rights	may	be	for	a	maximum	period	of	up	to	five	years	as	specified	in the	articles	of	association	or	relevant	shareholder	resolution.	The	current	exclusion	is	effective	until	the	earlier	of	our	next	annual	general	meeting	or	August	31,	2019. This	exclusion	would	need	to	be	renewed	by	our	shareholders	periodically	and	we	intend	to	renew	this	exclusion	at	each	annual	general	meeting.

English	law	also	requires	us	to	have	available	"distributable	reserves"	to	make	share	repurchases	or	pay	dividends	to	shareholders.		Distributable	reserves	may	be created	through	the	earnings	of	the	U.K.	parent	company	or	other	actions.		As	of	December	31,	2018,	we	had	distributable	reserves	in	excess	of	$2.2	billion.	While	it	is our	intention	to	maintain	a	sufficient	level	of	distributable	reserves	in	order	to	pay	dividends	on	our	ordinary	shares	and	make	share	repurchases,	there	is	no	assurance that	the	parent	company	level	will	maintain	the	necessary	level	of	distributable	reserves	to	do	so.	If	at	any	time	we	do	not	have	sufficient	distributable	reserves	to	declare and	pay	dividends,	we	may	undertake	a	reduction	in	capital	of	the	Company	to	reduce	the	amount	of	our	share	capital	and	non-distributable	reserves	and	to	create	a corresponding	increase	in	our	distributable	reserves	out	of	which	future	distributions	to	shareholders	could	be	made.

English	law	also	generally	prohibits	a	company	from	repurchasing	its	own	shares	by	way	of	"off-market	purchases"	without	the	prior	approval	of	our	shareholders. Such	approval	lasts	for	a	maximum	period	of	up	to	five	years.	Our	shares	are	traded	on	the	NYSE,	which	is	not	a	recognized	investment	exchange	in	the	U.K. Consequently,	any	repurchase	of	our	shares	is	currently	considered	an	"off	market	purchase."	The	current	authorization	expires	on	June	22,	2023.	Renewal	of	this authorization	will	be	sought	periodically.

# The	enforcement	of	civil	liabilities	against	us	may	be	more	difficult.

Because	we	are	a	public	limited	company	incorporated	under	the	laws	of	England	and	Wales,	investors	could	experience	more	difficulty	enforcing	judgments obtained	against	us	in	U.S.	courts	than	would	have	been	the	case	for	a	U.S.	company.	In	addition,	it	may	be	more	difficult	(or	impossible)	to	bring	some	types	of	claims against	us	in	courts	in	England	than	it	would	be	to	bring	similar	claims	against	a	U.S.	company	in	a	U.S.	court.

We	are	a	public	limited	company	incorporated	under	the	laws	of	England	and	Wales.	Therefore,	it	may	not	be	possible	to	effect	service	of	process	upon	us	within	the U.S.	in	order	to	enforce	judgments	of	U.S.	courts	against	us	based	on	the	civil	liability	provisions	of	the	U.S.	federal	securities	laws.

There	is	doubt	as	to	the	enforceability	in	England	and	Wales,	in	original	actions	or	in	actions	for	enforcement	of	judgments	of	U.S.	courts,	of	civil	liabilities	solely based	on	the	U.S.	federal	securities	laws.	The	English	courts	will,	however,	treat	any	amount	payable	by	us	under	U.S.	judgment	as	a	debt	and	new	proceedings	can	be commenced	in	the	English	courts	to	enforce	this	debt	against	us.	The	following	criteria	must	be	satisfied	in	order	for	the	English	court	to	enforce	the	debt	created	by	the U.S.	judgment:

•the	U.S.	court	having	had	jurisdiction	over	the	original	proceedings	according	to	English	conflicts	of	laws	principles	and	rules	of	English	private	international law	at	the	time	when	proceedings	were	initiated;

•the	U.S.	proceedings	not	having	been	brought	in	breach	of	a	jurisdiction	or	arbitration	clause	except	with	the	agreement	of	the	defendant	or	the	defendant's subsequent	submission	to	the	jurisdiction	of	the	court;

•the	U.S.	judgment	being	final	and	conclusive	on	the	merits	in	the	sense	of	being	final	and	unalterable	in	the	court	which	pronounced	it	and	being	for	a	definite sum	of	money;

•the	recognition	or	enforcement,	as	the	case	may	be,	of	the	U.S.	judgment	not	contravening	English	public	policy	in	a	sufficiently	significant	way	or contravening	the	Human	Rights	Act	1998	(or	any	subordinate	legislation	made	thereunder,	to	the	extent	applicable);

•the	U.S.	judgment	not	being	for	a	sum	payable	in	respect	of	taxes,	or	other	charges	of	a	like	nature,	or	in	respect	of	a	penalty	or	fine,	or	otherwise	based	on	a U.S.	law	that	an	English	court	considers	to	be	a	penal	or	revenue	law;

•the	U.S.	judgment	not	having	been	arrived	at	by	doubling,	trebling	or	otherwise	multiplying	a	sum	assessed	as	compensation	for	the	loss	or	damages	sustained,

and	not	otherwise	being	a	judgment	contrary	to	section	5	of	the	Protection	of	Trading	Interests	Act	1980	or	is	a	judgment	based	on	measures	designated	by	the Secretary	of	State	under	Section	1	of	that	Act;

•the	U.S.	judgment	not	having	been	obtained	by	fraud	or	in	breach	of	English	principles	of	natural

justice;

•the	U.S.	judgment	not	being	a	judgment	on	a	matter	previously	determined	by	an	English	court,	or	another	court	whose	judgment	is	entitled	to	recognition	(or

enforcement	as	the	case	may	be)	in	England,	in	proceedings	involving	the	same	parties	which	conflicts	with	an	earlier	judgment	of	such	court;

•the	party	seeking	enforcement	(being	a	party	who	is	not	ordinarily	resident	in	some	part	of	the	U.K.	or	resident	in	an	EU	Member	State)	providing	security	for costs,	if	ordered	to	do	so	by	the	English	courts;	and

•the	English	enforcement	proceedings	being	commenced	within	the	relevant	limitation

period.

If	an	English	court	gives	judgment	for	the	sum	payable	under	a	U.S.	judgment,	the	English	judgment	will	be	enforceable	by	methods	generally	available	for	this purpose.	These	methods	generally	permit	the	English	court	discretion	to	prescribe	the	manner	of	enforcement.	Also	note	that,	in	any	enforcement	proceedings,	the judgment	debtor	may	raise	any	counterclaim	that	could	have	been	brought	if	the	action	had	been	originally	brought	in	England	unless	the	subject	of	the	counterclaim was	in	issue	and	denied	in	the	U.S.	proceedings.

# Operational	Risks

The	economic	and	political	conditions	of	the	countries	and	regions	in	which	we	operate,	including	the	U.K.'s	expected	withdrawal	from	the	European	Union,	could	have an	adverse	impact	on	our	business,	financial	condition,	operating	results,	liquidity,	and	prospects	for	growth.

Our	operations	in	countries	undergoing	political	change	or	experiencing	economic	instability	are	subject	to	uncertainty	and	risks	that	could	materially	adversely affect	our	business.	These	risks	include,	particularly	in	emerging	markets,	the	possibility	we	would	be	subject	to	undeveloped	or	evolving	legal	systems,	unstable governments	and	economies,	and	potential	governmental	actions	affecting	the	flow	of	goods,	services,	and	currency.

Furthermore,	the	U.K.'s	withdrawal	from	the	European	Union,	which	is	legally	scheduled	for	March	29,	2019	("Brexit"),	has	created	uncertainty	about	the	future relationship	between	the	U.K.	and	the	European	Union.	As	the	U.K.	and	European	Union	continue	to	negotiate	the	terms	of	the	U.K.'s	withdrawal,	given	the	rejection	of the	proposed	deal	by	the	U.K.	Parliament	on	January	15,	there	remains	inevitable	uncertainty	on	topics	such	as	financial	laws	and	regulations,	tax	and	free	trade agreements,	immigration	laws,	and	employment	laws.	Our	publicly	traded	parent	is	incorporated	in	the	U.K.	and	we	have	significant	operations	and	a	substantial workforce	therein	and	therefore	enjoy	certain	benefits	based	on	the	U.K.'s	membership	in	the	European	Union.	The	lack	of	clarity	about	Brexit	and,	whether,	in	the future	U.K.	laws	and	regulations	are	recognized	in	the	EU,	creates	uncertainty	for	us	as	the	eventual	outcome	of	negotiations	may	affect	our	business	and	operations.	We may	be	required	to	incur	additional	expense	as	we	adapt	to	the	political	and	regulatory	environment	post-Brexit.	This	may	include	legal	entity	structure	changes, adjusting	the	way	we	engage	with	some	of	our	European	and	U.K.	clients,	or	choosing	to	re-locate	some	of	our	staff.	We	are	currently	examining	the	various	impacts	to our	business	and	operating	models	in	an	effort	to	develop	solutions	to	address	any	of	the	potential	outcomes	of	the	negotiations,	so	our	organization	can	continue	to provide	our	clients	with	the	services	and	expertise	they	require.	We	also	cannot	be	certain	that	regulators	in	other	European	Union	countries	will	grant	us	the	permissions or	licenses	we	seek	to	operate	our	business.	We	have	and	will	continue	to	invest	significant	time	and	resources	as	we	navigate	the	effects	of	Brexit,	and	the	uncertainty related	thereto,	on	our	business	and	operations.	A	less	orderly	Brexit	has	the	potential	to	adversely	affect	global	economic	conditions	and	the	stability	of	global	financial markets,	which	in	turn	could	have	a	material	adverse	effect	on	our	business,	financial	condition,	and	results	of	operations.

Additionally,	any	development	that	has	the	effect	of	devaluing	the	euro	or	British	pound	could	meaningfully	reduce	the	value	of	our	assets	and	reducing	the usefulness	of	liquidity	alternatives	denominated	in	that	currency	such	as	our	multicurrency	U.S.	credit	facility.	We	also	deposit	some	of	our	cash,	including	cash	held	in a	fiduciary	capacity,	with	certain	European	financial	institutions.	While	we	continuously	monitor	and	manage	exposures	associated	with	those	deposits,	to	the	extent	the uncertainty	surrounding	economic	stability	in	Europe	and	the	future	viability	of	the	euro	suddenly	and	adversely	impacts	those	financial	institutions,	some	or	all	of	those cash	deposits	could	be	at	risk.

We	may	not	realize	all	of	the	expected	benefits	from	our	restructuring	plan	and	other	operational	improvement	initiatives.

In	2017,	we	initiated	a	global	restructuring	plan	(the	"Restructuring	Plan")	in	connection	with	the	sale	of	the	Divested	Business.	The	Restructuring	Plan	is	intended to	streamline	operations	across	the	organization	and	deliver	greater	efficiency,	insight	and	connectivity.	We	expect	these	restructuring	activities	and	related	expenses	to affect	continuing	operations	through	the	forth	quarter	of	2019,	including	an	estimated	4,800	to	5,400	role	eliminations.	The	Restructuring	Plan	is	expected	to	result	in cumulative	costs	of	approximately	$1,225	million	through	the	end	of	the	Restructuring	Plan,	consisting	of	approximately	$450	million	in

employee	termination	costs,	$130	million	in	IT	rationalization	costs,	$65	million	in	real	estate	realization	costs,	$50	million	in	asset	impairment	costs	and	$530	million	in other	costs	associated	with	the	restructuring.	Included	in	the	estimated	$1,225	million	is	$100	million	of	estimated	non-cash	charges.

We	estimate	that	our	annualized	savings	from	the	Restructuring	Plan	and	other	operational	improvement	initiatives	will	be	approximately	$500	million	by	the	end of	2019.	Actual	total	costs,	savings,	and	timing	may	vary	from	these	estimates	due	to	changes	in	the	scope	or	assumptions	underlying	the	Restructuring	Plan	and	other operational	improvement	initiatives.		We	therefore	cannot	assure	that	we	will	achieve	the	targeted	savings.	Unanticipated	costs	or	unrealized	savings	in	connection	with the	Restructuring	Plan	and	other	operational	improvement	initiatives	could	adversely	affect	our	consolidated	financial	statements.

Our	success	depends	on	our	ability	to	retain	and	attract	experienced	and	qualified	personnel,	including	our	senior	management	team	and	other	professional	personnel.

We	depend,	in	material	part,	upon	the	members	of	our	senior	management	team	who	possess	extensive	knowledge	and	a	deep	understanding	of	our	business	and our	strategy,	as	well	as	the	colleagues	who	are	critical	to	developing	and	retaining	client	relationships.	The	unexpected	loss	of	services	of	any	of	these	senior	leaders could	have	a	disruptive	effect	adversely	impacting	our	ability	to	manage	our	business	effectively	and	execute	our	business	strategy.	Competition	for	experienced professional	personnel	is	intense,	and	we	are	constantly	working	to	retain	and	attract	these	professionals.	If	we	cannot	successfully	do	so,	our	business,	operating	results, and	financial	condition	could	be	adversely	affected.	While	we	have	plans	for	key	management	succession	and	long-term	compensation	plans	designed	to	retain	our senior	management	team	and	critical	colleagues,	if	our	succession	plans	and	retention	programs	do	not	operate	effectively,	our	business	could	be	adversely	affected.	We also	are	committed	to	diversity	and	inclusion	and	strive	to	maintain	an	equitable	work	environment	that	unlocks	the	full	potential	of	all	of	our	personnel.		If	we	are unsuccessful	in	maintaining	such	a	work	environment,	we	could	experience	difficulty	attracting	and	retaining	personnel,	which	could	have	a	negative	impact	on	our business.

# Our	global	operations	expose	us	to	various	international	risks	that	could	adversely	affect	our	business.

Our	operations	are	conducted	globally.	Accordingly,	we	are	subject	to	regulatory,	legal,	economic,	and	market	risks	associated	with	operating	in,	and	sourcing	from, foreign	countries,	including:

•difficulties	 in	 staffing	 and	 managing	 our	 foreign	 offices,	 including	 due	 to	 unexpected	 wage	 inflation	 or job turnover, and the increased travel, infrastructure,	and	legal	and	compliance	costs	and	risks	associated	with	multiple	international	locations;

•hyperinflation in certain foreign countries;

•conflicting	regulations	in	the	countries	in	which	we	do	business;

•imposition	of	investment	requirements	or	other	restrictions	by	foreign	governments;

•longer	payment	cycles;

•greater difficulties in collecting accounts receivable;

•insufficient demand for our services in foreign jurisdictions;

•our	 ability to	 execute	 effective	 and	 efficient	 cross-border	 sourcing	 of	 services	 on	 behalf	 of	 our clients;

•the	 reliance	 on	 or	 use	 of third	 parties to	 perform services	 on	 behalf	 of the Company;

•disparate	tax	regimes;

•restrictions	 on	 the import	 and	 export	 of technologies; and

•trade	barriers.

The	occurrence	of	natural	or	man-made	disasters	could	result	in	declines	in	business	and	increases	in	claims	that	could	adversely	affect	our	financial	condition	and results	of	operations.

We	are	exposed	to	various	risks	arising	out	of	natural	disasters,	including	earthquakes,	hurricanes,	fires,	floods,	tornadoes,	extreme	weather,	or	other	climate	events; pandemic	health	events,	and	man-made	disasters,	including	acts	of	terrorism,	civil	unrest,	violence,	military	actions,	and	cyber-terrorism.	The	continued	threat	of terrorism	and	other	events	or	disasters	may	cause	significant	volatility	in	global	financial	markets,	and	a	natural	or	man-made	disaster	could	trigger	energy	shortages, public	health	issues,	or	an	economic	downturn	or	instability	in	the	areas	directly	or	indirectly	affected	by	the	disaster.	These	consequences	could,	among	other	things, result	 in	a	decline	 in	business	and	 increased	claims	from	 those	areas.	They	could	also	result	 in	reduced	underwriting	capacity,	making	 it	more	difficult	for	our professionals	to	place	business.	Disasters	also	could	disrupt	public	and	private	infrastructure,	including	communications	and	financial	services,	which	could	disrupt	our normal	business	operations.

A	natural	or	man-made	disaster	also	could	disrupt	the	operations	of	our	counterparties	or	result	in	increased	prices	for	the	products	and	services	they	provide	to	us. In	addition,	a	disaster	could	adversely	affect	the	value	of	the	assets	in	our	investment	portfolio.	Finally,	a	natural	or	man-made	disaster	could	increase	the	incidence	or severity	of	E&O	claims	against	us.

# Our	inability	to	successfully	recover	should	we	experience	a	disaster	or	other	business	continuity	problem	could	cause	material	financial	loss,	loss	of	human	capital, regulatory	actions,	reputational	harm,	or	legal	liability.

Our	operations	are	dependent	upon	our	ability	to	protect	our	personnel,	offices,	and	technology	infrastructure	against	damage	from	business	continuity	events	that could	have	a	significant	disruptive	effect	on	our	operations.	Should	we	experience	a	local	or	regional	disaster	or	other	business	continuity	problem,	such	as	a	security incident	or	attack,	a	natural	disaster,	climate	event,	terrorist	attack,	pandemic,	power	loss,	telecommunications	failure,	or	other	natural	or	man-made	disaster,	our continued	success	will	depend,	in	part,	on	the	availability	of	our	personnel	and	office	facilities,	and	the	proper	functioning	of	computer	systems,	telecommunications, and	other	related	systems	and	operations.	In	events	like	these,	while	our	operational	size,	the	multiple	locations	from	which	we	operate,	and	our	existing	back-up systems	provide	us	with	some	degree	of	flexibility,	we	still	can	experience	near-term	operational	challenges	in	particular	areas	of	our	operations.	We	could	potentially lose	access	to	key	executives,	personnel,	or	client	data	or	experience	material	adverse	interruptions	to	our	operations	or	delivery	of	services	to	our	clients	in	a	disaster recovery	scenario.	A	disaster	on	a	significant	scale	or	affecting	certain	of	our	key	operating	areas	within	or	across	regions,	or	our	inability	to	successfully	recover	should we	experience	a	disaster	or	other	business	continuity	problem,	could	materially	interrupt	our	business	operations	and	cause	material	financial	loss,	loss	of	human	capital, regulatory	actions,	reputational	harm,	damaged	client	relationships,	or	legal	liability.

We	rely	on	complex	information	technology	systems	and	networks	to	operate	our	business.	Any	significant	system	or	network	disruption	due	to	a	breach	in	the	security of	our	information	technology	systems	could	have	a	negative	impact	on	our	reputation,	operations,	sales,	and	operating	results.

We	rely	on	the	efficient,	uninterrupted,	and	secure	operation	of	complex	information	technology	systems	and	networks,	some	of	which	are	within	the	Company	and some	of	which	are	outsourced	to	third	parties.	All	information	technology	systems	are	potentially	vulnerable	to	damage	or	interruption	from	a	variety	of	sources, including	but	not	limited	to	cyber-attacks,	computer	viruses,	security	breaches,	and	unauthorized	access	or	improper	actions	by	insiders	or	employees.	We	are	at	risk	of attack	by	a	growing	list	of	adversaries	through	increasingly	sophisticated	methods	of	attack.	Because	the	techniques	used	to	obtain	unauthorized	access	or	sabotage systems	change	frequently,	we	may	be	unable	to	anticipate	these	techniques,	implement	adequate	preventative	measures,	or	respond	quickly	enough	in	the	event	of	an incident	or	attack.	We	regularly	experience	attacks	to	our	systems	and	networks	and	have	from	time	to	time	experienced	cybersecurity	incidents,	such	as	computer viruses,	unauthorized	parties	gaining	access	to	our	information	technology	systems,	data	loss	via	malicious	and	non-malicious	methods,	and	similar	incidents,	which	to date	have	not	had	a	material	impact	on	our	business.	If	we	are	unable	to	efficiently	and	effectively	maintain	and	upgrade	our	system	safeguards,	we	may	incur unexpected	costs	and	certain	of	our	systems	may	become	more	vulnerable	to	unauthorized	access.	Problems	with	the	information	technology	systems	of	vendors, including	breakdowns	or	other	disruptions	in	communication	services	provided	by	a	vendor,	failure	of	a	vendor	to	handle	current	or	higher	volumes,	cyber-attacks,	and security	breaches	at	a	vendor	could	adversely	affect	our	ability	to	deliver	products	and	services	to	customers	and	otherwise	conduct	business.	Additionally,	we	are	a global	and	acquisitive	organization	and	we	therefore	might	not	adequately	identify	weaknesses	in	certain	of	our	information	systems,	including	those	of	targets	we acquire,	which	could	expose	us	to	unexpected	liabilities	or	make	our	own	systems	more	vulnerable	to	attack.	These	types	of	incidents	affecting	us	or	our	third-party vendors	could	result	in	intellectual	property	or	other	confidential	information	being	lost	or	stolen,	including	client	or	employee	personal	information,	or	company	data.	In addition,	we	may	not	be	able	to	detect	breaches	in	our	information	technology	systems	or	assess	the	severity	or	impact	of	a	breach	in	a	timely	manner.

We	have	implemented	various	measures	to	manage	our	risks	related	to	system	and	network	security	and	disruptions,	but	a	security	breach	or	a	significant	or extended	disruption	in	the	functioning	of	our	information	technology	systems	could	damage	our	reputation,	cause	us	to	lose	clients,	adversely	impact	our	operations, sales	and	operating	results,	and	require	us	to	incur	significant	expense	and	divert	resources	to	address	and	remediate	or	otherwise	resolve	such	issues.	Additionally,	in order	to	maintain	the	level	of	security,	service,	and	reliability	that	our	clients	require,	we	may	be	required	to	make	significant	additional	investments	in	our	information technology	system.

# Improper	disclosure	of	confidential,	personal,	or	proprietary	data	could	result	in	regulatory	scrutiny,	legal	liability,	or	harm	to	our	reputation.

One	of	our	significant	responsibilities	is	to	maintain	the	security	and	privacy	of	our	employees'	and	clients'	confidential	and	proprietary	information,	including confidential	information	about	our	clients'	and	employees'	compensation,	medical	information,	and	other	personally	identifiable	information.	We	maintain	policies, procedures,	and	technological	safeguards	designed	to	protect	the	security	and	privacy	of	this	information.	Nonetheless,	we	cannot	eliminate	the	risk	of	human	error, employee	or	vendor	malfeasance,	or	cyber-attacks	that	could	result	in	improper	access	to	or	disclosure	of	confidential,	personal,	or	proprietary	information.	Such	access or	disclosure	could	harm	our	reputation	and	subject	us	to	liability	under	our	contracts	and	laws	and	regulations	that	protect	personal	data,	resulting	in	increased	costs, loss	of	revenue,	and	loss	of	clients.	The	release	of	confidential	information	as	a	result	of	a	security	breach	could	also	lead	to	litigation	or	other	proceedings	against	us	by affected	individuals	or	business	partners,	or	by	regulators,	and	the	outcome	of	such	proceedings,	which	could	include	penalties	or	fines,	could	have	a	significant	negative impact	on	our	business.

In	many	jurisdictions,	including	in	the	European	Union	and	the	U.S.,	we	are	subject	to	laws	and	regulations	relating	to	the	collection,	use,	retention,	security,	and transfer	of	this	information.	These	laws	and	regulations	are	frequently	changing	and	are	becoming	increasingly	complex	and	sometimes	conflict	among	the	various jurisdictions	and	countries	in	which	we	provide	services	both	in	terms	of	substance	and	in	terms	of	enforceability.	This	makes	compliance	challenging	and	expensive. Additionally,	certain	 jurisdictions'	regulations	 include	notice	provisions	 that	may	require	us	 to	 inform	affected	clients	or	employees	 in	 the	event	of	a	breach	of confidential	information	before	we	fully	understand	or	appreciate	the	extent	of	the	breach.	These	notice	provisions	present	operational	challenges	and	related	risk.	In particular,	the	European	Union's	GDPR,	which	went	into	effect	in	May	2018,	caused	us	to	incur	significant	expenses	in	an	effort	to	implement	the	applicable	GDPR provisions	within	our	business	before	the	effective	date	causing	distraction	from	other	aspects	of	our	business.	In	addition,	non-compliance	with	GDPR	could	result	in proceedings	against	us	by	governmental	entities	or	others	and	additional	costs	in	connection	therewith.	We	expect	other	jurisdictions	in	which	we	operate	to	adopt regulations	governing	personal	data	and	information,	and	we	will	have	to	continue	to	incur	expenses	and	devote	resources	to	bring	our	practices	into	compliance	with such	future	regulations.	Our	failure	to	adhere	to	or	successfully	implement	processes	in	response	to	changing	regulatory	requirements	in	this	area	could	result	in	legal liability	or	impair	our	reputation	in	the	marketplace.	Further,	regulatory	initiatives	in	the	area	of	data	protection	are	more	frequently	including	provisions	allowing authorities	to	impose	substantial	fines	and	penalties,	and	therefore,	failure	to	comply	could	also	have	a	significant	financial	impact.

Our	business	performance	and	growth	plans	could	be	negatively	affected	if	we	are	not	able	to	effectively	apply	technology	in	driving	value	for	our	clients	through technology-based	solutions	or	gain	internal	efficiencies	through	the	effective	application	of	technology	and	related	tools.	Conversely,	investments	in	innovative	product offerings	may	fail	to	yield	sufficient	return	to	cover	their	investments.

Our	success	depends,	in	part,	on	our	ability	to	develop	and	implement	technology	solutions	that	anticipate	and	keep	pace	with	rapid	and	continuing	changes	in technology,	industry	standards,	and	client	preferences.	We	may	not	be	successful	in	anticipating	or	responding	to	these	developments	on	a	timely	and	cost-effective basis,	and	our	ideas	may	not	be	accepted	in	the	marketplace.	Additionally,	the	effort	to	gain	technological	expertise	and	develop	new	technologies	in	our	business requires	 us	 to	 incur	 significant	 expenses.	 If	 we	 cannot	 offer	 new	 technologies	 as	 quickly	 as	 our	 competitors	 or	 if	 our	 competitors	 develop	 more	 cost-effective technologies,	it	could	have	a	material	adverse	effect	on	our	ability	to	obtain	and	complete	client	engagements.	For	example,	we	have	invested	significantly	in	the development	of	our	proprietary	databases,	repositories	of	global	insurance	and	reinsurance	placement	information,	which	we	use	to	drive	results	for	our	clients	in	the insurance	and	reinsurance	placement	process.	Our	competitors	are	developing	competing	databases,	and	their	success	in	this	space	may	impact	our	ability	to	differentiate our	services	to	our	clients	through	the	use	of	unique	technological	solutions.	Innovations	in	software,	cloud	computing,	or	other	technologies	that	alter	how	our	services are	delivered	could	significantly	undermine	our	investment	in	this	business	if	we	are	slow	or	unable	to	take	advantage	of	these	developments.

We	 are	 continually	 developing	 and	 investing	 in	 innovative	 and	 novel	 service	 offerings	 that	 we	 believe	 will	 address	 needs	 that	 we	 identify	 in	 the	 markets. Nevertheless,	for	those	efforts	to	produce	meaningful	value,	we	are	reliant	on	a	number	of	other	factors,	some	of	which	our	outside	of	our	control.	For	example,	our Health	Solutions	revenue	line	has	invested	substantial	time	and	resources	in	launching	health	care	exchanges	under	the	belief	that	these	exchanges	will	serve	a	useful role	in	helping	corporations	and	individuals	in	the	U.S.	manage	their	growing	health	care	expenses.	In	order	for	these	exchanges	to	be	successful,	health	care	insurers	and corporate	and	individual	participants	have	to	deem	them	suitable,	and	whether	those	parties	will	find	them	suitable	will	be	subject	to	their	own	particular	circumstances.

We	rely	on	third	parties	to	perform	key	functions	of	our	business	operations	enabling	our	provision	of	services	to	our	clients.	These	third	parties	may	act	in	ways	that could	harm	our	business.

We	rely	on	third	parties,	and	in	some	cases	subcontractors,	to	provide	services,	data,	and	information	such	as	technology,	information	security,	funds	transfers,	data processing,	and	administration	and	support	functions	that	are	critical	to	the	operations	of	our	business.	These	third	parties	include	correspondents,	agents	and	other brokerage	and	intermediaries,	insurance	markets,	data	providers,	plan	trustees,	payroll	service	providers,	benefits	administrators,	software	and	system	vendors,	health plan	providers,	investment	managers,	and	providers	of	human	resource,	among	others.	As	we	do	not	fully	control	the	actions	of	these	third	parties,	we	are	subject	to	the risk	that	their	decisions,	actions,	or	inactions	may	adversely	impact	us	and	replacing	these	service	providers	could	create	significant	delay	and	expense.	A	failure	by	third parties	to	comply	with	service	level	agreements	or	regulatory	or	legal	requirements	in	a	high	quality	and	timely	manner,	particularly	during	periods	of	our	peak	demand for	their	services,	could	result	in	economic	and	reputational	harm	to	us.	In	addition,	we	face	risks	as	we	transition	from	in-house	functions	to	third-party	support functions	and	providers	that	there	may	be	disruptions	in	service	or	other	unintended	results	that	may	adversely	affect	our	business	operations.	These	third	parties	face their	own	technology,	operating,	business,	and	economic	risks,	and	any	significant	failures	by	them,	including	the	improper	use	or	disclosure	of	our	confidential	client, employee,	or	company	information,	could	cause	harm	to	our	reputation.	An	interruption	in	or	the	cessation	of	service	by	any	service	provider	as	a	result	of	systems failures,	cybersecurity	incidents,	capacity	constraints,	financial	difficulties,	or	for	any	other	reason	could	disrupt	our	operations,	impact	our	ability	to	offer	certain products	and	services,	and	result	in	contractual	or	regulatory	penalties,	liability	claims	from	clients,	or	employees,	damage	to	our	reputation,	and	harm	to	our	business.

# Our	business	is	exposed	to	risks	associated	with	the	handling	of	client	funds.

Certain	of	our	businesses	collect	premiums	from	insureds	and	remits	the	premiums	to	the	respective	insurers.	We	also	collect	claims	or	refunds	from	insurers	on behalf	of	insureds,	which	are	then	remitted	to	the	insureds.	Consequently,	at	any	given	time,	we	may	be	holding	and	managing	funds	of	our	clients.	This	function	creates a	risk	of	loss	arising	from,	among	other	things,	fraud	by	employees	or	third	parties,	execution	of	unauthorized	transactions,	errors	relating	to	transaction	processing,	or other	cybersecurity	events	or	security	breaches.	We	are	also	potentially	at	risk	in	the	event	the	financial	institution	in	which	we	hold	these	funds	suffers	any	kind	of insolvency	or	liquidity	event.	The	occurrence	of	any	of	these	types	of	events	in	connection	with	this	function	could	cause	us	financial	loss	and	reputational	harm.

In	connection	with	the	implementation	of	our	corporate	strategies,	we	face	risks	associated	with	the	acquisition	or	disposition	of	businesses,	the	entry	into	new	lines	of business,	the	integration	of	acquired	businesses,	and	the	growth	and	development	of	these	businesses.

In	pursuing	our	corporate	strategy,	we	often	acquire	other	businesses	or	dispose	of	or	exit	businesses	we	currently	own.	The	success	of	this	strategy	is	dependent upon	 our	 ability	 to	 identify	 appropriate	 acquisition	 and	 disposition	 targets,	 negotiate	 transactions	 on	 favorable	 terms,	 complete	 transactions	 and,	 in	 the	 case	 of acquisitions,	successfully	integrate	them	into	our	existing	businesses.	If	a	proposed	transaction	is	not	consummated,	the	time	and	resources	spent	pursuing	it	could adversely	result	in	missed	opportunities	to	locate	and	acquire	other	businesses.	If	acquisitions	are	made,	there	can	be	no	assurance	that	we	will	realize	the	anticipated benefits	of	such	acquisitions,	including,	but	not	limited	to,	revenue	growth,	operational	efficiencies,	or	expected	synergies.	If	we	dispose	of	or	otherwise	exit	certain businesses,	there	can	be	no	assurance	that	we	will	not	incur	certain	disposition	related	charges,	or	that	we	will	be	able	to	reduce	overhead	related	to	the	divested	assets.

From	time	to	time,	either	through	acquisitions	or	internal	development,	we	enter	new	lines	of	business	or	offer	new	products	and	services	within	existing	lines	of business.	These	new	lines	of	business	or	new	products	and	services	present	the	Company	with	additional	risks,	particularly	in	instances	where	the	markets	are	not	fully developed.	Such	risks	include	the	investment	of	significant	time	and	resources;	the	possibility	that	these	efforts	will	be	not	be	successful;	the	possibility	that	the marketplace	does	not	accept	our	products	or	services	or	that	we	are	unable	to	retain	clients	that	adopt	our	new	products	or	services;	and	the	risk	of	additional	liabilities associated	with	these	efforts.	In	addition,	many	of	the	businesses	that	we	acquire	and	develop	will	likely	have	significantly	smaller	scales	of	operations	prior	to	the implementation	of	our	growth	strategy.	If	we	are	not	able	to	manage	the	growing	complexity	of	these	businesses,	including	improving,	refining,	or	revising	our	systems and	operational	practices,	and	enlarging	the	scale	and	scope	of	the	businesses,	our	business	may	be	adversely	affected.	Other	risks	include	developing	knowledge	of	and experience	 in	 the	new	business,	 integrating	 the	acquired	business	 into	our	systems	and	culture,	recruiting	professionals,	and	developing	and	capitalizing	on	new relationships	with	experienced	market	participants.	External	factors,	such	as	compliance	with	new	or	revised	regulations,	competitive	alternatives,	and	shifting	market preferences	may	also	impact	the	successful	implementation	of	a	new	line	of	business.	Failure	to	manage	these	risks	in	the	acquisition	or	development	of	new	businesses could	materially	and	adversely	affect	our	business,	results	of	operations,	and	financial	condition.

# We	are	subject	to	various	risks	and	uncertainties	in	connection	with	the	sale	of	the	Divested	Business.

On	May	1,	2017,	we	sold	the	Divested	Business	to	an	entity	controlled	by	affiliates	of	The	Blackstone	Group	L.P.	(the	"Buyer").	This	transaction	carries	inherent risks,	including	the	risk	that	we	will	not	earn	the	$500	million	of	additional	consideration	or	otherwise	realize	the	intended	value	of	the	transaction,	as	well	as	risks connected	with	separating	the	Divested	Business	from	Aon.	We	are	party	to	a	transition	services	agreement	with	the	Buyer	and	there	are	risks	associated	with	this transition	services	agreement,	particularly	as	we	transition	off	of	the	Buyer's	systems	and	services	and	initiate	our	own	new	systems	and	processes,	which	could adversely	affect	our	business	and	results	of	operations.

Furthermore,	we	have	entered	into	ongoing	commercial	arrangements	with	the	Buyer.		If	we	do	not	realize	the	intended	benefits	of	these	arrangements,	it	could affect	our	results	of	operations	or	adversely	affect	our	relationship	with	clients,	partners,	colleagues,	and	other	third	parties.		Additionally,	if	the	Divested	Business	does not	deliver	the	level	of	service	to	which	our	clients	and	partners	are	accustomed,	it	could	adversely	affect	our	relationships	with	such	third	parties.

# Our	results	may	be	adversely	affected	by	changes	in	the	mode	of	compensation	in	the	insurance	industry.

In	the	past,	the	Attorney	General	of	the	State	of	New	York	brought	charges	against	members	of	the	insurance	brokerage	community.	These	actions	have	created uncertainty	concerning	longstanding	methods	of	compensating	insurance	brokers.	Given	that	the	insurance	brokerage	industry	has	faced	scrutiny	from	regulators	in	the past	over	its	compensation	practices,	and	the	transparency	and	discourse	to	clients	regarding	brokers'	compensation,	it	is	possible	that	regulators	may	choose	to	revisit the	same	or	other	practices	in	the	future.	If	they	do	so,	compliance	with	new	regulations	along	with	any	sanctions	that	might	be	imposed	for	past	practices	deemed improper	could	have	an	adverse	impact	on	our	future	results	of	operations	and	inflict	significant	reputational	harm	on	our	business.

# Risks	Related	to	Our	Ordinary	Shares

Transfers	of	the	Class	A	Ordinary	Shares	may	be	subject	to	stamp	duty	or	SDRT	in	the	U.K.,	which	would	increase	the	cost	of	dealing	in	the	Class	A	Ordinary	Shares.

Stamp	duty	reserve	taxes	("SDRT")	are	imposed	in	the	U.K.	on	certain	transfers	of	chargeable	securities	(which	include	shares	in	companies	incorporated	in	the U.K.)	at	a	rate	of	0.5	percent	of	the	consideration	paid	for	the	transfer.	Certain	transfers	of	shares	to	depositories	or	into	clearance	systems	are	charged	at	a	higher	rate	of 1.5	percent.

Our	Class	A	Ordinary	Shares	are	eligible	to	be	held	in	book	entry	form	through	the	facilities	of	Depository	Trust	Company	("DTC").	Transfers	of	shares	held	in book	entry	form	through	DTC	will	not	attract	a	charge	to	stamp	duty	or	SDRT	in	the	U.K.	A	transfer	of	the	shares	from	within	the	DTC	system	out	of	DTC	and	any subsequent	transfers	that	occur	entirely	outside	the	DTC	system	will	attract	a	charge	to	stamp	duty	at	a	rate	of	0.5	percent	of	any	consideration,	which	is	payable	by	the transferee	of	the	shares.	Any	such	duty	must	be	paid	(and	the	relevant	transfer	document	stamped	by	Her	Majesty's	Revenues	and	Customs	("HMRC"))	before	the transfer	can	be	registered	in	the	share	registers	of	Aon.	If	those	shares	are	redeposited	into	DTC,	the	redeposit	will	attract	stamp	duty	or	SDRT	at	a	rate	of	1.5	percent	of the	value	of	the	shares.

We	have	put	in	place	arrangements	to	require	that	shares	held	in	certificated	form	cannot	be	transferred	into	the	DTC	system	until	the	transferor	of	the	shares	has first	delivered	the	shares	to	a	depository	specified	by	us	so	that	SDRT	may	be	collected	in	connection	with	the	initial	delivery	to	the	depository.	Any	such	shares	will	be evidenced	by	a	receipt	issued	by	the	depository.	Before	the	transfer	can	be	registered	in	our	share	registers,	the	transferor	will	also	be	required	to	put	in	the	depository funds	to	settle	the	resultant	liability	to	SDRT,	which	will	be	charged	at	a	rate	of	1.5	percent	of	the	value	of	the	shares.

If	the	Class	A	Ordinary	Shares	are	not	eligible	for	continued	deposit	and	clearing	within	the	facilities	of	DTC,	then	transactions	in	our	securities	may	be	disrupted.

The	facilities	of	DTC	are	a	widely	used	mechanism	that	allow	for	rapid	electronic	transfers	of	securities	between	the	participants	in	the	DTC	system,	which	include many	large	banks	and	brokerage	firms.	We	believe	that	prior	to	our	reincorporation	in	the	U.K.	in	2012	(the	"Redomestication"),	approximately	99%	of	the	outstanding shares	of	common	stock	of	Aon	Corporation	were	held	within	the	DTC	system.	The	Class	A	Ordinary	Shares	of	Aon	plc	are,	at	present,	eligible	for	deposit	and	clearing within	the	DTC	system.	In	connection	with	the	closing	of	the	Redomestication,	we	entered	into	arrangements	with	DTC	whereby	we	agreed	to	indemnify	DTC	for	any stamp	duty	and/or	SDRT	that	may	be	assessed	upon	it	as	a	result	of	its	service	as	a	depository	and	clearing	agency	for	our	Class	A	Ordinary	Shares.	In	addition,	we	have obtained	a	ruling	from	HMRC	in	respect	of	the	stamp	duty	and	SDRT	consequences	of	the	reorganization,	and	SDRT	has	been	paid	in	accordance	with	the	terms	of	this ruling	in	respect	of	the	deposit	of	Class	A	Ordinary	Shares	with	the	initial	depository.	DTC	will	generally	have	discretion	to	cease	to	act	as	a	depository	and	clearing agency	for	the	Class	A	Ordinary	Shares.	If	DTC	determines	at	any	time	that	the	Class	A	Ordinary	Shares	are	not	eligible	for	continued	deposit	and	clearance	within	its facilities,	then	we	believe	the	Class	A	Ordinary	Shares	would	not	be	eligible	for	continued	listing	on	a	U.S.	securities	exchange	or	inclusion	in	the	S&P	500	and	trading in	the	Class	A	Ordinary	Shares	would

be	disrupted.	While	we	would	pursue	alternative	arrangements	to	preserve	our	listing	and	maintain	trading,	any	such	disruption	could	have	a	material	adverse	effect	on the	trading	price	of	the	Class	A	Ordinary	Shares.

# Item	1B.				Unresolved	Staff	Comments

# None.

# Item	2.				Properties

We	have	offices	in	various	locations	throughout	the	world.	Substantially	all	of	our	offices	are	located	in	leased	premises.	We	maintain	our	corporate	headquarters	at 122	Leadenhall	Street,	London,	England,	where	we	occupy	approximately	190,000	square	feet	of	space	under	an	operating	lease	agreement	that	expires	in	2034.	The following	are	additional	significant	leased	properties,	along	with	the	occupied	square	footage	and	expiration.

In	general,	no	difficulty	is	anticipated	in	negotiating	renewals	as	leases	expire	or	in	finding	other	satisfactory	space	if	the	premises	become	unavailable.	We	believe that	the	facilities	we	currently	occupy	are	adequate	for	the	purposes	for	which	they	are	being	used	and	are	well	maintained.	In	certain	circumstances,	we	may	have unused	 space	 and	 may	 seek	 to	 sublet	 such	 space	 to	 third	 parties,	 depending	 upon	 the	 demands	 for	 office	 space	 in	 the	 locations	 involved.	 See	 Note	 10	 "Lease Commitments"	of	 the	Notes	 to	Consolidated	Financial	Statements	 in	Part	II,	Item	8	of	 this	report	for	 information	with	respect	 to	our	 lease	commitments	as	of December	31,	2018.

# Item	3.				Legal	Proceedings

We	hereby	incorporate	by	reference	Note	17	"Claims,	Lawsuits,	and	Other	Contingencies"	of	the	Notes	to	Consolidated	Financial	Statements	in	Part	II,	Item	8	of this	report.

# Item	4.				Mine	Safety	Disclosure

Not	applicable.

# Executive	Officers	of	the	Registrant

The	executive	officers	of	Aon,	as	of	February	19,	2019	unless	otherwise	noted,	their	business	experience	during	the	last	five	years,	and	their	ages	and	positions	held are	set	forth	below.

Our	Class	A	Ordinary	Shares,	$0.01	nominal	value	per	share,	are	traded	on	the	NYSE	under	the	trading	symbol	AON.

On	February	15,	2019,	the	last	reported	sale	price	of	our	ordinary	shares	as	reported	by	the	NYSE	was	$171.97	per	share.	We	have	approximately	204	holders	of record	of	our	Class	A	Ordinary	Shares	as	of	February	15,	2019.

The	following	information	relates	to	the	repurchases	of	equity	securities	by	Aon	or	any	affiliated	purchaser	during	any	month	within	the	fourth	quarter	of	the	fiscal year	covered	by	this	report:

| Period | Total	Number	of	Shares<br>Purchased | Average	Price	Paid	per	Share	(1) | Total	Number	of	Shares<br>Purchased	as	Part	of	Publicly<br>Announced	Plans	or	Programs	(2) | Maximum	Dollar	Value	of	Shares<br>that	May	Yet	Be	Purchased	Under<br>the	Plans	or	Programs	(1)	(2) |
| :--- | :--- | :--- | :--- | :--- |
| 10/1/18\t–\t10/31/18 | 510,313 | $152.79 | 510,313 | $4,092,170,499 |
| 11/1/18\t–\t11/30/18 | 439,837 | $161.86 | 439,837 | $4,020,978,648 |
| 12/1/18\t–\t12/31/18 | 306,371 | $154.91 | 306,371 | $3,973,517,694 |
|  | 1,256,521 | $156.48 | 1,256,521 |  |

(1) Does	not	include	commissions	or	other	costs	paid	to	repurchase	shares.

(2) The	Repurchase	Program	was	established	in	April	2012	with $5.0	billion	in	authorized	repurchases,	and	was	increased	by	$5.0	billion	in	authorized	repurchases	in	each	of	November	2014	and February	2017,	for	a	total	of	$15.0	billion	in	repurchase	authorizations.

Information	relating	to	the	compensation	plans	under	which	equity	securities	of	Aon	are	authorized	for	issuance	is	set	forth	under	Part	III,	Item	12	"Security Ownership	of	Certain	Beneficial	Owners	and	Management	and	Related	Stockholder	Matters"	of	this	report	and	is	incorporated	herein	by	reference.

We	did	not	make	any	unregistered	sales	of	equity	in	2018.

| (millions,	except	per	share	data) | 2018 | 2017 | 2016 | 2015 | 2014 |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Income\tStatement\tData |  |  |  |  |  |
| Total\trevenue\tfrom\tcontinuing\toperations | $10,770 | $9,998 | $9,409 | $9,480 | $9,892 |
| Income\tfrom\tcontinuing\toperations | 1,100 | 435 | 1,253 | 1,253 | 1,312 |
| Net\tincome\tfrom\tdiscontinued\toperations | 74 | 828 | 177 | 169 | 119 |
| Net\tincome | 1,174 | 1,263 | 1,430 | 1,422 | 1,431 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | 40 | 37 | 34 | 37 | 34 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $1,134 | $1,226 | $1,396 | $1,385 | $1,397 |
| Basic\tNet\tIncome\tPer\tShare\tAttributable\tto\tAon\tShareholders |  |  |  |  |  |
| Continuing\toperations | $4.32 | $1.54 | $4.55 | $4.33 | $4.32 |
| Discontinued\toperations | 0.30 | 3.20 | 0.66 | 0.60 | 0.40 |
| Net\tincome | $4.62 | $4.74 | $5.21 | $4.93 | $4.73 |
| Diluted\tNet\tIncome\tPer\tShare\tAttributable\tto\tAon\tShareholders |  |  |  |  |  |
| Continuing\toperations | $4.29 | $1.53 | $4.51 | $4.28 | $4.27 |
| Discontinued\toperations | 0.30 | 3.17 | 0.65 | 0.60 | 0.40 |
| Net\tincome | $4.59 | $4.70 | $5.16 | $4.88 | $4.66 |
| Balance\tSheet\tData |  |  |  |  |  |
| Fiduciary\tassets\t(1) | $10,166 | $9,625 | $8,959 | $9,465 | $11,026 |
| Intangible\tassets\tincluding\tgoodwill | $9,320 | $10,091 | $9,300 | $8,795 | $9,338 |
| Total\tassets | $26,422 | $26,088 | $26,615 | $26,883 | $29,572 |
| Long-term\tdebt | $5,993 | $5,667 | $5,869 | $5,138 | $4,768 |
| Total\tequity | $4,219 | $4,648 | $5,532 | $6,059 | $6,527 |
| Class\tA\tOrdinary\tShares\tand\tOther\tData |  |  |  |  |  |
| Dividends\tpaid\tper\tshare | $1.56 | $1.41 | $1.29 | $1.15 | $0.92 |
| At\tyear-end: |  |  |  |  |  |
| Market\tprice,\tper\tshare | $145.36 | $134.00 | $111.53 | $92.21 | $94.83 |
| Shares\toutstanding | 240.1 | 247.6 | 262.0 | 269.8 | 280.0 |

(1) Represents	insurance	premium	receivables	from	clients	and	claims	receivables	from	insurance	carriers	as	well	as	cash	and	investments	held	in	a	fiduciary	capacity.

# EXECUTIVE	SUMMARY	OF	2018	FINANCIAL	RESULTS

Aon	is	a	leading	global	professional	services	firm	providing	a	broad	range	of	risk,	retirement,	and	health	solutions	underpinned	by	proprietary	data	and	analytics. Management	is	leading	a	set	of	initiatives	designed	to	strengthen	Aon	and	unite	the	firm	with	one	portfolio	of	capability	enabled	by	proprietary	data	and	analytics	and one	operating	model	to	deliver	additional	insight,	connectivity,	and	efficiency.

# Financial	Results

In	the	first	quarter	of	2018,	Aon	adopted	new	accounting	guidance	related	to	the	treatment	of	revenue	from	contracts	with	customers	that	was	applied	prospectively on	the	U.S.	GAAP	financial	statements	and	therefore	comparable	periods	have	not	been	restated.		Refer	to	Note	2	"Summary	of	Significant	Accounting	Principles	and Practices"	for	further	information	surrounding	the	quantitative	and	qualitative	impacts	of	adopting	the	new	accounting	guidance.

The	following	is	a	summary	of	our	2018	financial	results	from	continuing	operations	on	a	reported	basis:

•Revenue	increased	$772	million,	or	8%,	 to	$10,770	million	 in	2018	compared	to	2017,	 reflecting	5%	organic	revenue	growth,	a	2%	increase	related	to acquisitions,	net	of	divestitures,	and	a	1%	favorable	impact	from	translating	prior	year	period	results	at	current	period	foreign	exchange	rates	("foreign currency	translation").	Organic	revenue	growth	for	the	year	was	driven	by	growth	across	every	major	revenue	line,	with	particular	strength	in	Reinsurance Solutions,	Commercial	Risk	Solutions,	and	Health	Solutions.

•Operating	 expenses	increased	$293	million,	 or	3%,	 to	$9,226	million	 in	2018	 compared	 to	2017	due	primarily	 to	a	$172	million	increase	in	expenses related	to	acquisitions,	net	of	divestitures,	a	$75	million	increase	in	expense	related	to	legacy	litigation,	$71	million	of	accelerated	amortization	related	to tradenames,	a	$59	million	unfavorable	impact	from	foreign	currency	translation,	a	$14	million	increase	in	expense	to	support	GDPR	compliance,	and	an increase	in	expense	associated	with	5%	organic	revenue	growth,	partially	offset	by	a	$204	million	net	decrease	in	impairment	charges,	$195	million	of incremental	savings	related	to	restructuring	and	other	operational	improvement	initiatives,	and	a	$28	million	decrease	in	regulatory	and	compliance	costs.

•Operating	margin	increased	to	14.3%	in	2018	from	10.7%	in	2017,	including	an	increase	of	90	basis	points	resulting	from	adoption	of	the	new	revenue recognition	standard	in	2018.	The	underlying	increase	in	operating	margin	from	the	prior	year	is	primarily	driven	by	organic	revenue	growth	of	5%	and strong	core	operational	improvement,	partially	offset	by	an	increase	in	operating	expenses,	described	above.

•Diluted	earnings	per	share	from	continuing	operations	was	$4.29	per	share	during	the	twelve	months	of	2018	compared	to	$1.53	per	share	for	the	prior year	period,	including	an	increase	of	$0.32	per	share	resulting	from	the	adoption	of	the	new	revenue	recognition	standard.

•Cash	flow	provided	by	operating	activities	was	$1,686	million	in	2018,	an	increase	of	$1,017	million,	or	152%,	from	$669	million	in	2017.	The	prior	year included	 $940	 million	 of	 cash	 tax	 payments	 related	 to	 the	 sale	 of	 the	 Divested	 Business.	 Strong	 operational	 improvement	 and	 working	 capital improvements	in	both	receivables	and	payables	contributed	to	year-over-year	growth,	partially	offset	by	$145	million	of	incremental	cash	restructuring charges	and	$80	million	of	accelerated	pension	contributions.

We	focus	on	four	key	non-GAAP	metrics	that	we	communicate	to	shareholders:	organic	revenue	growth,	adjusted	operating	margins,	adjusted	diluted	earnings	per share,	and	free	cash	flow.	These	non-GAAP	metrics	should	be	viewed	in	addition	to,	not	instead	of,	our	Consolidated	Financial	Statements	and	Notes	thereto	(the "Financial	Statements").	The	following	is	our	measure	of	performance	against	these	four	metrics	from	continuing	operations	for	2018:

•Organic	revenue	growth,	a	non-GAAP	measure	defined	under	the	caption	"Review	of	Consolidated	Results	—	Organic	Revenue	Growth,"	was	5%	in 2018,	compared	to	4%	organic	growth	in	the	prior	year.	Organic	revenue	growth	was	driven	by	growth	across	every	major	revenue	line,	with	particular strength	in	Reinsurance	Solutions,	Commercial	Risk	Solutions,	and	Health	Solutions.

•Adjusted	operating	margin,	a	non-GAAP	measure	defined	under	the	caption	"Review	of	Consolidated	Results	—	Adjusted	Operating	Margin,"	was	25.0% in	2018,	compared	to	22.8%	in	the	prior	year.	The	increase	in	adjusted

operating	margin	primarily	reflects	organic	revenue	growth	of	5%,	core	operational	improvement,	and	$195	million	of	savings	related	to	restructuring	and other	operational	improvement	initiatives.

•Adjusted	diluted	earnings	per	share	from	continuing	operations,	a	non-GAAP	measure	defined	under	the	caption	"Review	of	Consolidated	Results	— Adjusted	Diluted	Earnings	per	Share,"	was	$8.16	per	share	in	2018,	an	increase	of	$1.69	per	share,	or	26%,	from	$6.47	per	share	in	2017.	The	increase demonstrates	strong	operational	performance	and	effective	capital	management,	highlighted	by	$1.4	billion	of	share	repurchase	during	2018,	partially offset	by	a	higher	adjusted	effective	tax	rate.

•Free	cash	flow,	a	non-GAAP	measure	defined	under	the	caption	"Review	of	Consolidated	Results	—	Free	Cash	Flow,"	was	$1,446	million	 in	2018,	an increase	of	$960	million,	or	198%,	from	$486	million	in	2017,	driven	by	an	increase	of	$1,017	million	in	cash	flow	in	operations,	partially	offset	by	a	$57 million	increase	in	capital	expenditures,	including	investments	in	our	operating	model.

# REVIEW	OF	CONSOLIDATED	RESULTS

# Summary	of	Results

Our	consolidated	results	are	as	follow:

| (millions) | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Revenue |  |  |  |
| Total\trevenue | $10,770 | $9,998 | $9,409 |
| Expenses |  |  |  |
| Compensation\tand\tbenefits | 6,103 | 6,003 | 5,514 |
| Information\ttechnology | 484 | 419 | 386 |
| Premises | 370 | 348 | 343 |
| Depreciation\tof\tfixed\tassets | 176 | 187 | 162 |
| Amortization\tand\timpairment\tof\tintangible\tassets | 593 | 704 | 157 |
| Other\tgeneral\texpenses | 1,500 | 1,272 | 1,036 |
| Total\toperating\texpenses | 9,226 | 8,933 | 7,598 |
| Operating\tincome | 1,544 | 1,065 | 1,811 |
| Interest\tincome | 5 | 27 | 9 |
| Interest\texpense | (278) | (282) | (282) |
| Other\tincome\t(expense) | (25) | (125) | (137) |
| Income\tfrom\tcontinuing\toperations\tbefore\tincome\ttaxes | 1,246 | 685 | 1,401 |
| Income\ttaxes | 146 | 250 | 148 |
| Net\tincome\tfrom\tcontinuing\toperations | 1,100 | 435 | 1,253 |
| Net\tincome\tfrom\tdiscontinued\toperations | 74 | 828 | 177 |
| Net\tincome | 1,174 | 1,263 | 1,430 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | 40 | 37 | 34 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $1,134 | $1,226 | $1,396 |

# Consolidated	Results	for	2018	Compared	to	2017

# Revenue

Total	revenue	increased	$772	million,	 or	8%,	 to	$10,770	million	 in	2018,	compared	to	$9,998	million in	2017.	 The	increase	was	driven	by	5%	organic	revenue growth,	a	2%	increase	related	to	acquisitions,	net	of	divestitures,	and	a	1%	favorable	impact

from	foreign	currency	translation.	Organic	revenue	growth	for	the	year	was	driven	by	growth	across	every	major	revenue	line,	with	particular	strength	in	Reinsurance Solutions,	Commercial	Risk	Solutions,	and	Health	Solutions.

Commercial	Risk	Solutions	revenue	increased	$483	million,	or	12%,	to	$4,652	million	in	2018,	compared	to	$4,169	million	in	2017.	Organic	revenue	growth	was 6%	in	2018	driven	by	growth	across	every	major	geography,	with	particular	strength	in	U.S.	Retail	driven	by	record	new	business	generation	and	strong	management	of the	renewal	book	portfolio.	Results	also	include	double-digit	growth	in	both	cyber	solutions	and	transaction	liability,	two	specific	areas	of	investment	to	support increasing	client	demand.

Reinsurance	Solutions	revenue	increased	$134	million,	or	9%,	to	$1,563	million	in	2018,	compared	to	$1,429	million	in	2017.	Organic	revenue	growth	was	7%	in 2018	driven	by	net	new	business	generation	in	treaty	and	strong	growth	in	facultative	placements,	partially	offset	by	a	modest	decline	in	capital	markets	transactions given	the	prior	year	period	benefited	from	record	catastrophe	bond	issuance	during	the	mid-year	renewal	season.

Retirement	Solutions	revenue	increased	$110	million,	or	6%,	to	$1,865	million	in	2018,	compared	to	$1,755	million	in	2017.	Organic	revenue	growth	was	2%	in 2018	driven	by	solid	growth	in	core	actuarial	retirement	and	in	the	talent	practice,	as	well	as	modest	growth	in	investment	consulting.

Health	Solutions	revenue	increased	$81	million,	or	5%,	to	$1,596	million	in	2018,	compared	to	$1,515	million	in	2017.	Organic	revenue	growth	was	5%	 in	2018 driven	primarily	by	strong	growth	in	health	&	benefits	brokerage,	in	both	the	Americas	and	internationally,	and	in	the	health	care	exchange	business	driven	by	new	client wins	in	both	the	active	and	retiree	exchanges.

Data	&	Analytic	Services	revenue	decreased	$35	million,	or	3%,	to	$1,105	million	in	2018,	compared	to	$1,140	million	in	2017.	Organic	revenue	growth	was	3%	in 2018	driven	by	strong	growth	globally	across	Affinity.

# Compensation	and	Benefits

Compensation	and	benefits	increased	$100	million,	or	2%,	in	2018	compared	to	2017.	The	increase	was	primarily	driven	by	a	$145	million	increase	in	expenses related	to	acquisitions,	net	of	divestitures,	a	$50	million	unfavorable	impact	from	foreign	currency	translation,	and	an	increase	in	expense	associated	with	5%	organic revenue	growth,	partially	offset	by	a	$184	million	decrease	in	restructuring	costs,	$182	million	of	incremental	savings	related	to	restructuring	and	other	operational improvement	initiatives,	and	a	$51	million	decrease	related	to	the	adoption	of	the	new	revenue	recognition	standard	in	2018.

# Information	Technology

Information	technology,	which	represents	costs	associated	with	supporting	and	maintaining	our	infrastructure,	increased	$65	million,	or	16%,	in	2018	compared	to 2017.	The	increase	was	primarily	driven	by	a	$16	million	increase	in	expenses	related	to	acquisitions,	net	of	divestitures,	a	$14	million	increase	in	restructuring	costs,	an increase	in	expense	associated	with	5%	organic	revenue	growth,	and	investments	supporting	long-term	growth	initiatives,	partially	offset	by	$1	million	of	incremental savings	related	to	restructuring	and	other	operational	improvement	initiatives.

# Premises

Premises,	which	represents	the	cost	of	occupying	offices	in	various	locations	throughout	the	world,	increased	$22	million,	or	6%,	in	2018	compared	to	2017.	The increase	was	primarily	driven	by	a	$20	million	increase	in	restructuring	costs,	and	a	$10	million	increase	in	expenses	related	to	acquisitions,	net	of	divestitures,	partially offset	by	$16	million	of	incremental	savings	related	to	restructuring	and	other	operational	improvement	initiatives.

# Depreciation	of	Fixed	Assets

Depreciation	 of	 fixed	 assets	 primarily	 relates	 to	 software,	 leasehold	 improvements,	 furniture,	 fixtures	 and	 equipment,	 computer	 equipment,	 buildings,	 and automobiles.	Depreciation	of	fixed	assets	decreased	$11	million,	or	6%,	 in	2018	compared	to	2017.	 The	decrease	was	primarily	driven	by	a	$13	million	decrease	in restructuring	costs,	partially	offset	by	a	$4	million	increase	related	to	acquisitions,	net	of	divestitures.

# Amortization	and	Impairment	of	Intangible	Assets

Amortization	and	impairment	of	intangibles	primarily	relates	to	finite-lived	tradenames	and	customer-related,	contract-based,	and	technology	assets.	Amortization and	 impairment	 of	 intangibles	decreased	$111	million,	 or	16%,	 in	2018	 compared	 to	2017.	 The	decrease	 was	 primarily	 driven	 by	 a	 net	$204	million	 decrease	 in impairment	charges,	partially	offset	by	a	$71	million	increase	in	accelerated	amortization	related	to	tradenames.

# Other	General	Expenses

Other	general	expenses	increased	$228	million,	or	18%,	in	2018	compared	to	2017.	The	increase	was	primarily	driven	by	a	$151	million	increase	in	restructuring costs,	a	$75	million	increase	in	legacy	litigation,	an	$11	million	increase	in	expense	to	support	GDPR	regulatory	compliance,	and	an	increase	in	expense	associated	with 5%	organic	revenue	growth,	partially	offset	by	a	$28	million	decrease	in	costs	related	to	regulatory	and	compliance	matters.

# Interest	Income

Interest	income	represents	income	earned	on	operating	cash	balances	and	other	income-producing	investments.	It	does	not	include	interest	earned	on	funds	held	on behalf	of	clients.	Interest	income	was	$5	million	in	2018,	a	decrease	of	$22	million,	or	81%,	from	2017,	due	primarily	to	additional	income	earned	on	the	balance	of	cash proceeds	from	the	Divested	Business	in	the	prior	year	period.

# Interest	Expense

Interest	expense,	which	represents	the	cost	of	our	debt	obligations,	was	$278	million	in	2018,	a	decrease	of	$4	million,	or	1%,	from	2017.	This	decrease	was	driven primarily	by	the	maturity	of	higher	interest	rate	term	debt	in	Q1	2018	partially	offset	by	interest	on	a	higher	average	commercial	paper	outstanding	compared	to	the	prior year.

# Other	Income	(Expense)

Other	expense	decreased	$100	million,	or	80%,	to	$25	million	in	2018	compared	to	2017.	Other	expense	in	2018	includes,	among	other	things,	$49	million	of	losses on	certain	financial	instruments	and	$6	million	in	net	losses	on	the	disposition	of	businesses,	partially	offset	by	a	$25	million	favorable	impact	of	exchange	rates	on	the remeasurement	of	assets	and	liabilities	in	non-functional	currencies	and	$4	million	of	equity	earnings.	Other	expense	in	2017	includes	$86	million	of	pension	and	other post-retirement	expense,	a	$37	million	unfavorable	impact	of	exchange	rates	on	the	remeasurement	of	assets	and	liabilities	in	non-functional	currencies,	and	$16	million in	net	losses	on	the	disposition	of	businesses,	partially	offset	by	$12	million	in	equity	earnings.

# Income	From	Continuing	Operations	before	Income	Taxes

Due	to	factors	discussed	above,	income	from	continuing	operations	before	income	taxes	was	$1,246	million	in	2018,	an	82%	increase	from	$685	million	in	2017.

# Income	Taxes	From	Continuing	Operations

The	effective	tax	rate	on	net	income	from	continuing	operations	was	11.7% in	2018	 and	36.5% in	2017.	The	primary	drivers	of	the	2018	tax	rate	include	the following:

•The	geographical	distribution	of	 income	 including	restructuring	charges,	 legacy	 litigation,	and the impairment	of	certain	assets	and liabilities	previously classified	as	held	for	sale	as	well	as	the	post-enactment	date	impacts	of	the	Tax	Reform	Act.

•Certain	discrete	items	including	the	tax	benefit	associated	with	the	sale	of	certain	assets	and	liabilities	previously	classified	as	held	for	sale	and	the	impact	of share-based	payments	offset	by	the	net	tax	expense	from	finalizing	the	impact	of	the	enactment	of	the	Tax	Reform	Act	and	changes	in	valuation	allowances.

The	2017	tax	rate	reflects	changes	in	the	geographical	distribution	of	income	including	restructuring	charges	and	the	impairment	and	amortization	of	tradenames,	the impact	of	share-based	payments,	and	the	provisional	estimate	of	the	enactment	date	impact	of	the	Tax	Reform	Act.

# Income	from	Discontinued	Operations,	Net	of	Tax

Net	income	from	discontinued	operations	decreased	$754	million	to	$74	million	compared	to	2017	due	to	the	execution	of	the	sale	of	the	Divested	Business	on	May 2,	2017.

# Net	Income	Attributable	to	Aon	Shareholders

Total	revenue	increased	by	6%,	or	$589	million,	to	$9,998	million	in	2017,	compared	to	$9,409	million	in	2016.	The	increase	was	driven	by	4%	organic	revenue growth	and	a	2%	increase	related	to	acquisitions,	net	of	divestitures.	Organic	revenue	growth	for	the	year	was	driven	by	growth	across	every	major	revenue	line,	with particular	strength	in	Reinsurance	Solutions,	Health	Solutions,	and	Data	&	Analytic	Services.

Commercial	Risk	Solutions	revenue	increased	$240	million,	or	6%,	to	$4,169	million	in	2017,	compared	to	$3,929	million	in	2016.	Organic	revenue	growth	was	2% in	2017	driven	by	growth	across	nearly	every	geography,	with	particular	strength	in	U.S.	Retail	driven	by	record	new	business	generation	and	strong	management	of	the renewal	book	portfolio.

Reinsurance	Solutions	revenue	increased	$68	million,	or	5%,	to	$1,429	million	in	2017,	compared	to	$1,361	million	in	2016.	Organic	revenue	growth	was	6%	in 2017	driven	by	growth	across	all	major	product	lines,	highlighted	by	continued	net	new	business	generation	in	the	treaty	portfolio,	growth	in	facultative	placements,	and strong	growth	in	capital	markets.

Retirement	Solutions	revenue	increased	$48	million,	or	3%,	to	$1,755	million	in	2017,	compared	to	$1,707	million	in	2016.	Organic	revenue	growth	was	3%	in	2017 driven	 by	 double-digit	 growth	 in	 investment	 consulting,	 primarily	 for	 delegated	 investment	 management,	 as	 well	 as	 solid	 growth	 in	 the	 Talent,	 Rewards,	 and Performance	practice.

Health	Solutions	revenue	increased	$145	million,	or	11%,	to	$1,515	million	in	2017,	compared	to	$1,370	million	in	2016.	Organic	revenue	growth	was	7%	in	2017 driven	primarily	by	strong	growth	in	health	&	benefits	brokerage,	in	both	the	Americas	and	internationally.

Data	&	Analytic	Services	revenue	increased	$90	million,	or	9%,	to	$1,140	million	in	2017,	compared	to	$1,050	million	in	2016.	Organic	revenue	growth	was	6%	in 2017	driven	by	strong	growth	across	Affinity,	with	particular	strength	in	the	U.S.

Compensation	and	benefits	increased	$489	million	in	2017,	or	9%,	compared	to	2016.	The	increase	was	primarily	driven	by	$299	million	of	restructuring	charges,	a $154	million	increase	in	expenses	related	to	acquisitions,	net	of	divestitures,	and	an	increase	in	expense	associated	with	4%	organic	revenue	growth,	partially	offset	by $104	million	of	savings	related	 to	restructuring	and	other	operational	 improvement	 initiatives	and	a	$92	million	decrease	 in	expenses	related	 to	certain	pension settlements.

Information	technology,	which	represents	costs	associated	with	supporting	and	maintaining	our	infrastructure,	increased	$33	million	in	2017,	or	9%,	compared	to 2016.	The	increase	was	primarily	driven	by	$33	million	of	restructuring	costs,	a	$7	million	increase	in	expenses	related	to	acquisitions,	net	of	divestitures,	as	well	as investments	in	growth,	partially	offset	by	$37	million	of	savings	related	to	restructuring	and	other	operational	improvement	initiatives.

Premises,	which	represents	the	cost	of	occupying	offices	in	various	locations	throughout	the	world,	increased	$5	million	in	2017,	 or	1%,	compared	to	2016.	The increase	was	primarily	driven	by	an	$11	million	increase	in	expenses	related	to	acquisitions,	net	of	divestitures,	and	$8	million	of	restructuring	costs,	partially	offset	by $3	million	of	savings	related	to	restructuring	and	other	operational	improvement	initiatives.

Depreciation	 of	 fixed	 assets	 primarily	 relates	 to	 software,	 leasehold	 improvements,	 furniture,	 fixtures	 and	 equipment,	 computer	 equipment,	 buildings,	 and automobiles.	Depreciation	of	fixed	assets	increased	$25	million	in	2017,	or	15%,	compared	to	2016.	The	increase	was	primarily	driven	by	$26	million	of	restructuring costs	and	a	$14	million	increase	in	expenses	associated	with	acquisitions,	net	of	divestitures,	partially	offset	by	$1	million	of	savings	related	to	restructuring	and	other operational	improvement	initiatives	as	well	as	a	decrease	as	we	continue	to	optimize	our	real	estate	and	information	technology	portfolio.

Amortization	and	impairment	of	intangibles	primarily	relates	to	finite-lived	tradenames	and	customer-related,	contract-based,	and	technology	assets.	Amortization and	 impairment	 of	 intangibles	increased	$547	million	 for	 the	 year,	 or	348%,	 compared	 to	2016.	 The	increase	 was	 primarily	 driven	 by	 a	$380	 million	 non-cash impairment	charge	to	the	indefinite	lived	tradenames	associated	with	the	Divested	Business,	$143	million	of	accelerated	amortization	related	to	tradenames,	and	an increase	associated	with	recent	acquisitions,	net	of	divestitures.

Other	general	expenses	increased	$236	million	in	2017,	or	23%,	compared	to	2016.	The	increase	was	primarily	driven	by	$131	million	of	restructuring	costs,	a	$71 million	increase	in	expenses	associated	with	acquisitions,	net	of	divestitures,	$28	million	of	costs	related	to	regulatory	and	compliance	matters,	and	an	increase	in expense	associated	with	4%	organic	revenue	growth,	partially	offset	by	$20	million	of	savings	related	to	restructuring	and	other	operational	improvement	initiatives	and a	$15	million	decrease	in	expenses	related	to	the	sale	of	the	Divested	Business	in	the	prior	year	period.

Interest	income	represents	income	earned	on	operating	cash	balances	and	other	income-producing	investments.	It	does	not	include	interest	earned	on	funds	held	on behalf	of	clients.	Interest	income	was	$27	million	in	2017,	an	increase	of	$18	million,	or	200%,	from	2016,	due	primarily	to	additional	income	earned	on	the	balance	of cash	proceeds	from	the	Divested	Business.

Interest	expense,	which	represents	the	cost	of	our	debt	obligations,	was	$282	million	in	2017,	similar	to	the	prior	year	period.

Other	expense	decreased	$12	million	 from	$137	million	 in	2016	 to	$125	million	 in	2017.	 Other	 expense	 in	2017	 includes,	among	other	 things,	$86	million	of pension	 and	 other	 post-retirement	 expense,	 a	$37	million	unfavorable	 impact	of	exchange	rates	on	 the	 remeasurement	 of	 assets	 and	 liabilities	 in	 non-functional currencies,	and	$16	million	in	net	losses	on	the	disposition	of	businesses,	partially	offset	by	$12	million	in	equity	earnings.	Other	expense	in	2016	includes	$173	million of	pension	and	other	post-retirement	expense	and	$14	million	of	losses	on	certain	financial	instruments,	partially	offset	by	$39	million	in	net	gains	on	the	disposition	of businesses	and	$13	million	in	equity	earnings.

Due	to	factors	discussed	above,	income	from	continuing	operations	before	income	taxes	was	$685	million	in	2017,	a	51%	decrease	from	$1,401	million	in	2016.

The	effective	 tax	rate	on	net	 income	from	continuing	operations	was	36.5%	 in	2017	 and	10.6%	 in	2016.	 The	2017	rate	reflects	changes	 in	 the	geographical distribution	of	income,	the	impact	of	share-based	payments,	and	the	provisional	estimate	of	the	impact	of	U.S.	tax	reform	based	on	Aon's	initial	analysis	of	the	Tax	Cuts and	Jobs	Act.	The	2016	rate	reflects	changes	in	the	geographical	distribution	of	income	and	the	impact	from	certain	pension	settlements	in	the	second	and	fourth quarters.

On	February	9,	2017,	the	Company	entered	into	a	Purchase	Agreement	with	the	Buyer	to	sell	the	Divested	Business.	The	Company	has	retrospectively	classified	the results	of	the	Divested	Business	as	discontinued	operations	in	the	Company's	Consolidated	Statements	of	Income	for	all	periods	presented.	Income	from	discontinued operations,	net	of	tax,	increased	$651	million	to	$828	million	compared	to	2016.	This	increase	was	primarily	driven	by	the	gain	on	sale	of	the	Divested	Business.

# Non-GAAP	Metrics

In	our	discussion	of	consolidated	results,	we	sometimes	refer	to	certain	non-GAAP	supplemental	information	derived	from	consolidated	financial	information specifically	related	to	organic	revenue	growth,	adjusted	operating	margin,	adjusted	diluted	earnings	per	share,	free	cash	flow,	and	the	impact	of	foreign	exchange	rate fluctuations	on	operating	results.	This	non-GAAP	supplemental	information	should	be	viewed	in	addition	to,	not	instead	of,	our	Financial	Statements.

# Organic	Revenue	Growth

We	use	supplemental	information	related	to	organic	revenue	growth	to	help	us	and	our	investors	evaluate	business	growth	from	existing	operations.	Organic revenue	growth	is	a	non-GAAP	measure	that	includes	the	impact	of	intercompany	activity	and	excludes	the	impact	of	the	adoption	of	the	new	revenue	recognition standard,	changes	in	foreign	exchange	rates,	acquisitions,	divestitures,	transfers	between	revenue	lines,	and	fiduciary	investment	income.	This	supplemental	information related	to	organic	revenue	growth	represents	a	measure	not	in	accordance	with	U.S.	GAAP	and	should	be	viewed	in	addition	to,	not	instead	of,	our

Financial	Statements.	Industry	peers	provide	similar	supplemental	information	about	their	revenue	performance,	although	they	may	not	make	identical	adjustments.	A reconciliation	of	this	non-GAAP	measure	to	the	reported	Total	revenue	is	as	follows	(in	millions,	except	percentages):

|  | Dec	31,	2018 | Dec	31,	2017 | %	Change | Revenue<br>Recognition(1) | Less:<br>Currency<br>Impact	(2) | Less:	Fiduciary<br>Investment<br>Income	(3) | Less:	Acquisitions,<br>Divestitures	&amp;	Other | Organic<br>Revenue<br>Growth	(4) |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| Commercial\tRisk\tSolutions | $4,652 | $4,169 | 12\t% | —\t% | 1% | —% | 5\t% | 6% |
| Reinsurance\tSolutions | 1,563 | 1,429 | 9 | (1) | 2 | 1 | — | 7 |
| Retirement\tSolutions | 1,865 | 1,755 | 6 | — | 1 | — | 3 | 2 |
| Health\tSolutions | 1,596 | 1,515 | 5 | (1) | — | — | 1 | 5 |
| Data\t&amp;\tAnalytic\tServices | 1,105 | 1,140 | (3) | — | — | — | (6) | 3 |
| Elimination | (11) | (10) | NA | NA | NA | NA | NA | NA |
| Total\trevenue | $10,770 | $9,998 | 8\t% | —\t% | 1% | —% | 2\t% | 5% |

|  | Dec	31,	2017 | Dec	31,	2016 | %	Change | Less:	Currency<br>Impact	(2) | Less:	Fiduciary<br>Investment	Income	(3) | Less:	Acquisitions,<br>Divestitures	&amp;	Other | Organic	Revenue<br>Growth	(4) |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| Commercial\tRisk\tSolutions | $4,169 | $3,929 | 6% | —\t% | —% | 4\t% | 2% |
| Reinsurance\tSolutions | 1,429 | 1,361 | 5 | — | — | (1) | 6 |
| Retirement\tSolutions | 1,755 | 1,707 | 3 | (1) | — | 1 | 3 |
| Health\tSolutions | 1,515 | 1,370 | 11 | — | — | 4 | 7 |
| Data\t&amp;\tAnalytic\tServices | 1,140 | 1,050 | 9 | — | — | 3 | 6 |
| Elimination | (10) | (8) | NA | NA | NA | NA | NA |
| Total\trevenue | $9,998 | $9,409 | 6% | —\t% | —% | 2\t% | 4% |

(1) Revenue	Recognition	represents	the	impact	of	Aon's	adoption	of	the	new	revenue	recognition	standard,	effective	for	Aon	in	the	first	quarter	of	2018.

(2) Currency	impact	is	determined	by	translating	prior	period's	revenue	at	this	period's	foreign	exchange	rates.

(4) Organic	revenue	growth	includes	the	impact	of	intercompany	activity	and	excludes	the	impact	of	the	adoption	of	the	new	revenue	recognition	standard,	changes	in	foreign	exchange	rates, acquisitions,	divestitures,	transfers	between	revenue	lines,	and	fiduciary	investment	income.

# Adjusted	Operating	Margin

We	use	adjusted	operating	margin	as	a	non-GAAP	measure	of	core	operating	performance	of	the	Company.	Adjusted	operating	margin	excludes	the	impact	of certain	items,	as	listed	below,	because	management	does	not	believe	these	expenses	reflect	our	core	operating	performance.	This	supplemental	information	related	to adjusted	operating	margin	represents	a	measure	not	in	accordance	with	U.S.	GAAP,	and	should	be	viewed	in	addition	to,	not	instead	of,	our	Financial	Statements.

A	reconciliation	of	this	non-GAAP	measure	to	reported	operating	margins	is	as	follows	(in	millions,	except	percentage	data):

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Revenue\tfrom\tcontinuing\toperations | $10,770 | $9,998 | $9,409 |
| Operating\tincome\tfrom\tcontinuing\toperations\t-\tas\treported | $1,544 | $1,065 | $1,811 |
| Amortization\tand\timpairment\tof\tintangible\tassets(3) | 593 | 704 | 157 |
| Restructuring | 485 | 497 | — |
| Legacy\tlitigation | 75 | — | — |
| Regulatory\tand\tcompliance\tmatters | — | 28 | — |
| Transaction\tcosts | — | — | 15 |
| Operating\tincome\tfrom\tcontinuing\toperations\t-\tas\tadjusted | $2,697 | $2,294 | $1,983 |
| Operating\tmargin\tfrom\tcontinuing\toperations\t-\tas\treported | 14.3% | 10.7% | 19.2% |
| Operating\tmargin\tfrom\tcontinuing\toperations\t-\tas\tadjusted | 25.0% | 22.9% | 21.1% |

# Adjusted	Diluted	Earnings	per	Share

We	also	use	adjusted	diluted	earnings	per	share	as	a	non-GAAP	measure	of	our	core	operating	performance.	Adjusted	diluted	earnings	per	share	excludes	the	items identified	above,	plus	related	income	taxes	because	management	does	not	believe	these	expenses	are	representative	of	our	core	earnings.	This	supplemental	information related	to	adjusted	diluted	earnings	per	share	represents	a	measure	not	in	accordance	with	U.S.	GAAP	and	should	be	viewed	in	addition	to,	not	instead	of,	our	Financial Statements.

A	reconciliation	of	this	non-GAAP	measure	to	reported	Diluted	earnings	per	share	is	as	follows	(in	millions,	except	per	share	data	and	percentages):

| (millions,	except	per	share	data) | U.S.	GAAP | Adjustments | Non-GAAP	Adjusted |
| :--- | :--- | :--- | :--- |
| Operating\tincome\tfrom\tcontinuing\toperations | $1,544 | $1,153 | $2,697 |
| Interest\tincome | 5 | — | 5 |
| Interest\texpense | (278) | — | (278) |
| Other\tincome\t(expense)\t(1) | (25) | 37 | 12 |
| Income\tbefore\tincome\ttaxes\tfrom\tcontinuing\toperations | 1,246 | 1,190 | 2,436 |
| Income\ttaxes\t(2) | 146 | 233 | 379 |
| Net\tincome\tfrom\tcontinuing\toperations | 1,100 | 957 | 2,057 |
| Net\tincome\t(loss)\tfrom\tdiscontinued\toperations\t(3) | 74 | (82) | (8) |
| Net\tincome | 1,174 | 875 | 2,049 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | 40 | — | 40 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $1,134 | $875 | $2,009 |
| Diluted\tnet\tincome\t(loss)\tper\tshare\tattributable\tto\tAon\tshareholders |  |  |  |
| Continuing\toperations | $4.29 | $3.87 | $8.16 |
| Discontinued\toperations | 0.30 | (0.33) | (0.03) |
| Net\tincome | $4.59 | $3.54 | $8.13 |
| Weighted\taverage\tordinary\tshares\toutstanding\t—\tdiluted | 247.0 | — | 247.0 |
| Effective\ttax\trates\t(3) |  |  |  |
| Continuing\toperations\t-\tU.S.\tGAAP | 11.7% |  | 15.6% |
| Discontinued\toperations\t-\tU.S.\tGAAP | 15,949.3% |  | 29.7% |

| (millions,	except	per	share	data) | U.S.	GAAP | Adjustments | Non-GAAP	Adjusted |
| :--- | :--- | :--- | :--- |
| Operating\tincome\tfrom\tcontinuing\toperations | $1,065 | $1,229 | $2,294 |
| Interest\tincome | 27 | — | 27 |
| Interest\texpense | (282) | — | (282) |
| Other\tincome\t(expense)\t(1) | (125) | 128 | 3 |
| Income\tbefore\tincome\ttaxes\tfrom\tcontinuing\toperations | 685 | 1,357 | 2,042 |
| Income\ttaxes\t(2) | 250 | 55 | 305 |
| Net\tincome\tfrom\tcontinuing\toperations | 435 | 1,302 | 1,737 |
| Net\tincome\t(loss)\tfrom\tdiscontinued\toperations\t(3) | 828 | (772) | 56 |
| Net\tincome | 1,263 | 530 | 1,793 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | 37 | — | 37 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $1,226 | $530 | $1,756 |
| Diluted\tnet\tincome\t(loss)\tper\tshare\tattributable\tto\tAon\tshareholders |  |  |  |
| Continuing\toperations | $1.53 | $4.99 | $6.52 |
| Discontinued\toperations | 3.17 | (2.95) | 0.22 |
| Net\tincome | $4.70 | $2.04 | $6.74 |
| Weighted\taverage\tordinary\tshares\toutstanding\t—\tdiluted | 260.7 | — | 260.7 |
| Effective\ttax\trates\t(3) |  |  |  |
| Continuing\toperations\t-\tU.S.\tGAAP | 36.5% |  | 14.9% |
| Discontinued\toperations\t-\tU.S.\tGAAP | 58.9% |  | 11.7% |

| (millions,	except	per	share	data) | U.S.	GAAP | Adjustments | Non-GAAP	Adjusted |
| :--- | :--- | :--- | :--- |
| Operating\tincome\tfrom\tcontinuing\toperations | $1,811 | $172 | $1,983 |
| Interest\tincome | 9 | — | 9 |
| Interest\texpense | (282) | — | (282) |
| Other\tincome\t(expense)\t(1) | (137) | 220 | 83 |
| Income\tbefore\tincome\ttaxes\tfrom\tcontinuing\toperations | 1,401 | 392 | 1,793 |
| Income\ttaxes\t(2) | 148 | 102 | 250 |
| Net\tincome\tfrom\tcontinuing\toperations | 1,253 | 290 | 1,543 |
| Net\tincome\tfrom\tdiscontinued\toperations\t(3) | 177 | 94 | 271 |
| Net\tincome | 1,430 | 384 | 1,814 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | 34 | — | 34 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $1,396 | $384 | $1,780 |
| Diluted\tnet\tincome\t(loss)\tper\tshare\tattributable\tto\tAon\tshareholders |  |  |  |
| Continuing\toperations | $4.51 | $1.07 | $5.58 |
| Discontinued\toperations | 0.65 | 0.36 | 1.01 |
| Net\tincome | $5.16 | $1.43 | $6.59 |
| Weighted\taverage\tordinary\tshares\toutstanding\t—\tdiluted | 270.3 | — | 270.3 |
| Effective\ttax\trates\t(3) |  |  |  |
| Continuing\toperations\t-\tU.S.\tGAAP | 10.6% |  | 13.9% |
| Discontinued\toperations\t-\tU.S.\tGAAP | 34.0% |  | 30.2% |

(1) Adjusted	Other	income	(expense)	excludes	Pension	settlement	charges	of	$37	million,	$128	million,	and	$220	million,	for	the	years	ended	2018,	2017,	and	2016,	respectively.

(2) Adjusted	items	are	generally	taxed	at	the	estimated	annual	effective	tax	rate,	except	for	the	applicable	tax	impact	associated	with	estimated	Restructuring	Plan	expenses,	legacy	litigation, accelerated	tradename	amortization,	impairment	charges	and	non-cash	pension	settlement	charges,	which	are	adjusted	at	the	related	jurisdictional	rates.	In	addition,	tax	expense	excludes	the	tax impacts	from	the	sale	of	certain	assets	and	liabilities	previously	classified	as	held	for	sale	as	well	as	the	tax	adjustments	recorded	to	finalize	the	2017	accounting	for	the	enactment	date	impact	of the	Tax	Reform	Act	recorded	pursuant	to	SAB	118.

(3) Adjusted	net	income	from	discontinued	operations	excludes	the	gain	on	sale	of	discontinued	operations	of	$ 82	million,	$779	million,	and	$0	million	for	the	years	ended	2018,	2017,	and	2016, respectively.	Adjusted	net	income	from	discontinued	operations	excludes	intangible	asset	amortization	of	$0	million,	$11	million,	and	$120	million	for	the	twelve	months	ended	December	31, 2018,	2017,	and	2016,	respectively.	The	effective	tax	rate	was	further	adjusted	for	the	applicable	tax	impact	associated	with	the	gain	on	sale	and	intangible	asset	amortization,	as	applicable.

# Free	Cash	Flow

We	use	free	cash	flow,	defined	as	cash	flow	provided	by	operations	minus	capital	expenditures,	as	a	non-GAAP	measure	of	our	core	operating	performance	and cash	generating	capabilities	of	our	business	operations.	This	supplemental	information	related	to	free	cash	flow	represents	a	measure	not	in	accordance	with	U.S.	GAAP and	should	be	viewed	in	addition	to,	not	instead	of,	our	Financial	Statements.	The	use	of	this	non-GAAP	measure	does	not	imply	or	represent	the	residual	cash	flow	for discretionary	expenditures.	A	reconciliation	of	this	non-GAAP	measure	to	cash	flow	provided	by	operations	is	as	follows	(in	millions):

| Years	Ended	December	31 | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Cash\tProvided\tby\tContinuing\tOperating\tActivities | $1,686 | $669 | $1,829 |
| Capital\tExpenditures\tUsed\tfor\tContinuing\tOperations | (240) | (183) | (156) |
| Free\tCash\tFlow\tProvided\tBy\tContinuing\tOperations | $1,446 | $486 | $1,673 |

# Impact	of	Foreign	Currency	Exchange	Rate	Fluctuations

We	conduct	business	in	more	than	120	countries	and	sovereignties	and,	because	of	this,	foreign	currency	exchange	rate	fluctuations	have	a	significant	impact	on	our business.	Foreign	currency	exchange	rate	movements	may	be	significant	and	may	distort	true	period-to-period	comparisons	of	changes	in	revenue	or	pretax	income. Therefore,	to	give	financial	statement	users	meaningful	information	about	our	operations,	we	have	provided	an	illustration	of	the	impact	of	foreign	currency	exchange rate	fluctuations	on	our	financial	results.	The	methodology	used	to	calculate	this	impact	isolates	the	impact	of	the	change	in	currencies	between	periods	by	translating	the prior	year's	revenue,	expenses,	and	net	income	using	the	current	year's	foreign	currency	exchange	rates.

Translating	prior	year	results	at	current	year	foreign	currency	exchange	rates,	currency	fluctuations	had	a	$0.08	favorable	impact	on	net	income	per	diluted	share during	the	year	ended	December	31,	2018.	Currency	fluctuations	had	a	$0.12	favorable	impact	on	net	income	per	diluted	share	during	the	year	ended	December	31, 2017,	when	2016	results	were	translated	at	2017	rates.	Currency	fluctuations	had	no	impact	on	net	income	per	diluted	share	during	the	year	ended	December	31,	2016, when	2015	results	were	translated	at	2016	rates.

Translating	prior	year	results	at	current	year	foreign	currency	exchange	rates,	currency	fluctuations	had	a	$0.09	favorable	impact	on	adjusted	net	income	per	diluted share	during	the	year	ended	December	31,	2018.	Currency	fluctuations	had	a	$0.08	favorable	impact	on	adjusted	net	income	per	diluted	share	during	the	year	ended December	31,	2017,	when	2016	results	were	translated	at	2017	rates.	Currency	fluctuations	had	a	$0.04	unfavorable	impact	on	adjusted	net	income	per	diluted	share during	the	year	ended	December	31,	2016,	when	2015	results	were	translated	at	2016	rates.	These	translations	are	performed	for	comparative	purposes	only	and	do	not impact	the	accounting	policies	or	practices	for	amounts	included	in	the	Financial	Statements.

# Competition	and	Markets	Authority

The	U.K.'s	competition	regulator,	the	Competition	and	Markets	Authority	(the	"CMA"),	conducted	a	market	investigation	into	the	supply	and	acquisition	of investment	consulting	and	fiduciary	management	services,	including	those	offered	by	Aon	and	its	competitors	in	the	U.K.,	to	assess	whether	any	feature	or	combination of	features	in	the	target	market	prevents,	restricts,	or	distorts	competition.		The	CMA	issued	a	final	report	on	December	12,	2018.		The	CMA	will	draft	a	series	of	orders that	will	set	out	the	detailed	remedies,	expected	in	first	quarter	of	2019,	when	they	will	be	subject	to	further	public	consultation.	We	do	not	anticipate	the	remedies	to have	a	significant	impact	on	the	Company's	consolidated	financial	position	or	business.

# Financial	Conduct	Authority

The	FCA	is	conducting	a	market	study	to	assess	how	effectively	competition	is	working	in	the	wholesale	insurance	broker	sector	in	the	U.K.	in	which	Aon,	through its	subsidiaries,	participates.	The	FCA	has	indicated	that	the	purpose	of	a	market	study	is	to	assess	the	extent	to	which	the	market	is	working	well	in	the	interests	of customers	and	to	identify	features	of	the	market	that	may	impact	competition.		Depending	on	the	study's	findings,	the	FCA	may	require	remedies	in	order	to	correct	any features	found

to	be	preventing,	restricting,	or	distorting	competition.	The	study	is	ongoing	and	we	are	unable	to	estimate	the	impact,	if	any,	on	Aon's	business	at	this	time.

# LIQUIDITY	AND	FINANCIAL	CONDITION

# Liquidity

# Executive	Summary

We	believe	that	our	balance	sheet	and	strong	cash	flow	provide	us	with	adequate	liquidity.	Our	primary	sources	of	liquidity	are	cash	flows	from	operations, available	cash	reserves,	and	debt	capacity	available	under	our	credit	facilities.	Our	primary	uses	of	liquidity	are	operating	expenses,	restructuring	activities,	capital expenditures,	acquisitions,	share	repurchases,	pension	obligations,	and	shareholder	dividends.	We	believe	that	cash	flows	from	operations,	available	credit	facilities,	and the	 capital	 markets	 will	 be	 sufficient	 to	 meet	 our	 liquidity	 needs,	 including	 principal	 and	 interest	 payments	 on	 debt	 obligations,	 capital	 expenditures,	 pension contributions,	and	anticipated	working	capital	requirements,	for	the	foreseeable	future.

Cash	on	our	balance	sheet	includes	funds	available	for	general	corporate	purposes,	as	well	as	amounts	restricted	as	to	their	use.	Funds	held	on	behalf	of	clients	in	a fiduciary	capacity	are	segregated	and	shown	together	with	uncollected	insurance	premiums	and	claims	in	Fiduciary	assets	in	the	Consolidated	Statements	of	Financial Position,	with	a	corresponding	amount	in	Fiduciary	liabilities.

In	our	capacity	as	an	insurance	broker	or	agent,	we	collect	premiums	from	insureds	and,	after	deducting	our	commission,	remit	the	premiums	to	the	respective insurance	underwriters.	We	also	collect	claims	or	refunds	from	underwriters	on	behalf	of	insureds,	which	are	then	returned	to	the	insureds.	Unremitted	insurance premiums	and	claims	are	held	by	us	in	a	fiduciary	capacity.	In	addition,	some	of	our	outsourcing	agreements	require	us	to	hold	funds	on	behalf	of	clients	to	pay obligations	on	their	behalf.	The	levels	of	fiduciary	assets	and	liabilities	can	fluctuate	significantly	depending	on	when	we	collect	the	premiums,	claims,	and	refunds, make	payments	to	underwriters	and	insureds,	and	collect	funds	from	clients	and	make	payments	on	their	behalf,	and	upon	the	impact	of	foreign	currency	movements. Fiduciary	assets,	because	of	their	nature,	are	generally	invested	in	very	liquid	securities	with	highly	rated,	credit-worthy	financial	institutions.	In	our	Consolidated Statements	of	Financial	Position,	the	amount	we	report	for	Fiduciary	assets	and	Fiduciary	liabilities	are	equal.	Our	Fiduciary	assets	included	cash	and	short-term investments	of	$3.9	billion	and	$3.7	billion	at	December	31,	2018	and	2017,	respectively,	and	fiduciary	receivables	of	$6.3	billion	and	$5.9	billion	at	December	31,	2018 and	2017,	respectively.	While	we	earn	investment	income	on	the	fiduciary	assets	held	in	cash	and	investments,	the	cash	and	investments	cannot	be	used	for	general corporate	purposes.

We	maintain	multicurrency	cash	pools	with	third-party	banks	in	which	various	Aon	entities	participate.	Individual	Aon	entities	are	permitted	to	overdraw	on	their individual	accounts	provided	the	overall	global	balance	does	not	fall	below	zero.	At	December	31,	2018,	non-U.S.	cash	balances	of	one	or	more	entities	were	negative; however,	the	overall	balance	was	positive.

The	following	table	summarizes	our	Fiduciary	assets,	non-fiduciary	Cash	and	cash	equivalents,	and	Short-term	investments	as	of	December	31,	2018	(in	millions):

| Asset	Type | Cash	and	Cash<br>Equivalents | Short-term<br>Investments | Fiduciary<br>Assets | Total |
| :--- | :--- | :--- | :--- | :--- |
| Certificates\tof\tdeposit,\tbank\tdeposits\tor\ttime\tdeposits | $656 | $— | $2,279 | $2,935 |
| Money\tmarket\tfunds | — | 172 | 1,587 | 1,759 |
| Cash\tand\tshort-term\tinvestments | 656 | 172 | 3,866 | 4,694 |
| Fiduciary\treceivables | — | — | 6,300 | 6,300 |
| Total | $656 | $172 | $10,166 | $10,994 |

Cash	and	cash	equivalents	decreased	$100	million	in	2018	compared	to	2017.	A	summary	of	our	cash	flows	provided	by	and	used	for	continuing	operations from	operating,	investing,	and	financing	activities	is	as	follows	(in	millions):

|  | 2018 | 2017 |
| :--- | :--- | :--- |
| Cash\tprovided\tby\toperating\tactivities\t-\tcontinuing\toperations | $1,686 | $669 |
| Cash\tprovided\tby\tinvesting\tactivities\t-\tcontinuing\toperations | $31 | $2,806 |
| Cash\tused\tfor\tfinancing\tactivities\t-\tcontinuing\toperations | $(1,699) | $(3,265) |
| Effect\tof\texchange\trates\tchanges\ton\tcash\tand\tcash\tequivalents | $(118) | $69 |

# Operating	Activities

Net	cash	provided	by	operating	activities	for	continuing	operations	during	the	twelve	months	ended	December	31,	2018	increased	$1,017	million,	or	152%,	from	the prior	year	to	$1,686	million.	This	amount	represents	net	income	reported,	as	adjusted	for	gains	or	losses	on	sales	of	businesses,	share-based	compensation	expense, depreciation	expense,	amortization	and	impairments,	and	other	non-cash	income	and	expenses,	as	well	as	changes	in	working	capital	that	relate	primarily	to	the	timing	of payments	of	accounts	payable	and	accrued	liabilities	and	the	collection	of	receivables.

# Pension	Contributions

Pension	cash	contributions	were	$252	million	for	the	twelve	months	ended	December	31,	2018,	which	includes	our	acceleration	of	contributions	to	the	qualified U.S.	pension	plan,	as	compared	to	cash	contributions	of	$146	million	and	a	non-cash	contribution	of	$80	million	for	the	twelve	months	ended	December	31,	2017.	In 2019,	we	expect	to	contribute	approximately	$145	million	to	our	pension	plans,	with	the	majority	attributable	to	non-U.S.	pension	plans,	which	are	subject	to	changes	in foreign	exchange	rates.

# Restructuring	Plan

In	2017,	we	initiated	a	global	restructuring	plan	(the	"Restructuring	Plan")	in	connection	with	the	sale	of	the	Divested	Business.	The	Restructuring	Plan	is	intended to	streamline	operations	across	the	organization	and	deliver	greater	efficiency,	insight,	and	connectivity.	We	expect	these	restructuring	activities	and	related	expenses	to affect	continuing	operations	through	2019,	including	an	estimated	4,800	to	5,400	role	eliminations.	In	the	fourth	quarter	of	2018,	we	expanded	the	Restructuring	Plan, which	 resulted	 in	 additional	 expected	 costs	 of	 approximately	$200	million,	 consisting	 of	$150	million	 of	 cash	 investment	 and	$50	million	 of	 non-cash	 charges. Annualized	estimated	savings	increased	$50	million	as	a	result	of	the	expanded	program.	We	do	not	expect	any	further	adjustments	to	the	total	estimated	program	costs or	annualized	savings	through	the	remainder	of	the	program,	which	will	be	completed	in	the	fourth	quarter	of	2019.

We	expect	the	Restructuring	Plan	to	result	in	cumulative	costs	of	approximately	$1,225	million	through	the	end	of	the	plan,	consisting	of	approximately	$450 million	in	employee	termination	costs,	$130	million	in	technology	rationalization	costs,	$65	million	in	real	estate	consolidation	costs,	$50	million	in	non-cash	asset impairments,	such	as	expense	taken	on	software	no	longer	in	use,	and	$530	million	in	other	costs	including	certain	separation	costs	associated	with	the	sale	of	the Divested	Business.	We	estimate	that	our	annualized	savings	from	the	Restructuring	Plan	and	other	operational	improvement	initiatives	will	be	approximately	$500 million	by	the	end	of	2019.

The	following	table	summarizes	restructuring	and	separation	costs	by	type	that	have	been	incurred	through	December	31,	2018	and	are	estimated	to	be	incurred through	the	end	of	the	Restructuring	Plan	(in	millions).	Estimated	remaining	costs	by	type	may	be	revised	in	future	periods	as	these	assumptions	are	updated:

|  | Year	Ended<br>December	31,	2018 | Inception	to	Date | Estimated<br>Remaining	Costs | Estimated	Total<br>Cost	(1) |
| :--- | :--- | :--- | :--- | :--- |
| Workforce\treduction | $115 | $414 | $36 | $450 |
| Technology\trationalization\t(2) | 47 | 80 | 50 | 130 |
| Lease\tconsolidation\t(2) | 28 | 36 | 29 | 65 |
| Asset\timpairments | 13 | 39 | 11 | 50 |
| Other\tcosts\tassociated\twith\trestructuring\tand\tseparation\t(2)\t(3) | 282 | 413 | 117 | 530 |
| Total\trestructuring\tand\trelated\texpenses | $485 | 982 | $243 | $1,225 |

(1) Actual	costs,	when	incurred,	may	vary	due	to	changes	in	the	assumptions	built	into	the	Restructuring	Plan.	Significant	assumptions	that	may	change	when	plans	are	finalized	and	implemented include,	but	are	not	limited	to,	changes	in	severance	calculations,	changes	in	the	assumptions	underlying	sublease	loss	calculations	due	to	changing	market	conditions,	and	changes	in	the	overall analysis	that	might	cause	the	Company	to	add	or	cancel	component	initiatives.

(2) Total	contract	termination	costs	incurred	under	the	Restructuring	Plan	associated	with	Technology	rationalizations,	Lease	consolidations,	and	Other	costs	associated	with	restructuring	and separation,	respectively,	for	the	twelve	months	ended	December	31,	2018	were	$5	million,	$25	million,	and	$85	million;	and	since	inception	of	the	Restructuring	Plan,	were	$6	million,	$33 million,	 and	$88	million,	respectively.	Total	estimated	contract	termination	costs	expected	to	be	incurred	under	the	Restructuring	Plan	associated	with	Technology	rationalizations,	Lease consolidations,	and	Other	costs	associated	with	restructuring	and	separation,	respectively,	are	$15	million,	$80	million,	and	$95	million.

(3) Other	costs	associated	with	the	Restructuring	Plan	include	those	to	separate	the	Divested	Business,	as	well	as	moving	costs	and	consulting	and	legal	fees.	These	costs	are	generally	recognized      when	incurred.

As	of	December	31,	2018,	our	liabilities	for	the	Restructuring	Plan	were	as	follows	(in	millions):

# Investing	Activities

Cash	flow	provided	by	investing	activities	in	continuing	operations	was	$31	million	during	the	twelve	months	ended	December	31,	2018,	 a	decrease	 of	$2,775 million	compared	to	prior	year.	The	primary	drivers	of	cash	flow	used	for	investing	activities	are	acquisition	of	businesses,	purchases	of	short-term	investments,	capital expenditures,	and	payments	for	investments.	The	primary	drivers	of	cash	flow	provided	by	investing	activities	are	sales	of	businesses,	sales	of	short-term	investments, and	proceeds	from	investments.	The	gains	and	losses	corresponding	to	cash	flows	provided	by	proceeds	from	investments	and	used	for	payments	for	investments	are primarily	recognized	in	Other	income	(expense)	in	the	Consolidated	Statements	of	Income.

# Short-term	Investments

Short-term	investments	decreased	$357	million	at	December	31,	2018	as	compared	to	December	31,	2017.	As	disclosed	in	Note	16	"Fair	Value	Measurements	and Financial	Instruments"	of	the	Financial	Statements	contained	in	Part	II,	Item	8	of	this	report,	the	majority	of	our	investments	carried	at	fair	value	are	money	market funds.	These	money	market	funds	are	held	throughout	the	world	with	various	financial	institutions.	We	are	not	aware	of	any	market	liquidity	issues	that	would materially	impact	the	fair	value	of	these	investments.

# Acquisitions	and	Dispositions	of	Businesses

During	2018,	the	Company	completed	the	acquisition	of	eight	businesses	for	consideration	of	$58	million,	net	of	cash	acquired,	and	completed	the	disposition	of four	business	for	a	net	cash	outflow	of	$10	million.

During	2017,	the	Company	completed	the	acquisition	of	seventeen	businesses	for	consideration	of	$1,029	million,	net	of	cash	acquired,	and	the	sale	of	nine businesses	for	$4,246	million.

# Capital	Expenditures

The	Company's	additions	to	fixed	assets,	including	capitalized	software,	which	amounted	to	$240	million	in	2018	and	$183	million	in	2017,	primarily	related	to computer	equipment	purchases,	the	refurbishing	and	modernizing	of	office	facilities,	and	software	development	costs.

# Financing	Activities

Cash	flow	used	for	financing	activities	in	continuing	operations	during	the	twelve	months	ended	December	31,	2018	 was	$1,699	million,	 an	increase	 of	$1,566 million	compared	to	prior	year.	The	primary	drivers	of	cash	flow	used	for	financing	activities	are	share	repurchases,	issuances	of	debt,	net	of	repayments,	dividends	paid to	shareholders,	issuances	of	shares	for	employee	benefit	plans,	transactions	with	noncontrolling	interests,	and	other	financing	activities.

# Share	Repurchase	Program

Aon	has	a	share	repurchase	program	authorized	by	the	Company's	Board	of	Directors.	The	Repurchase	Program	was	established	in	April	2012	with	$5.0	billion	in authorized	repurchases,	and	was	increased	by	$5.0	billion	in	authorized	repurchases	in	each	of	November	2014	and	February	2017,	for	a	total	of	$15.0	billion	in repurchase	authorizations.

The	following	table	summarizes	the	Company's	Share	Repurchase	activity	(in	millions,	except	per	share	data):

|  | Twelve	months	ended	December	31 |  |
| :--- | :--- | :--- |
|  | 2018 | 2017\t(1) |
| Shares\trepurchased | 10.0 | 18.0 |
| Average\tprice\tper\tshare | $143.94 | $133.67 |
| Costs\trecorded\tto\tretained\tearnings |  |  |
| Total\trepurchase\tcost | $1,447 | $2,403 |
| Additional\tassociated\tcosts | 7 | 12 |
| Total\tcosts\trecorded\tto\tretained\tearnings | $1,454 | $2,415 |

(1) Included	in	the	18.0	million	shares	repurchased	during	the	twelve	months	ended	December	31,	2017	were	0.1	million	shares	that	did	not	settle	until	January	2018.	These	shares	were	settled	at	an average	price	per	share	of	$134.41	and	total	cost	of	$15.9	million.

At	December	31,	2018,	the	remaining	authorized	amount	for	share	repurchase	under	the	Repurchase	Program	was	approximately	$4.0	billion.	Under	the	Repurchase Program,	the	Company	has	repurchased	a	total	of	118.3	million	shares	for	an	aggregate	cost	of	approximately	$11.0	billion.

# Borrowings

Total	debt	at	December	31,	2018	was	$6.2	billion,	an	increase	of	$278	million	compared	to	December	31,	2017.	Commercial	paper	activity	during	the	years	ended December	31,	2018	and	2017	is	as	follows	(in	millions):

|  | 2018 | 2017 |
| :--- | :--- | :--- |
| Total\tissuances(1) | $5,400 | $1,648 |
| Total\trepayments | (5,118) | (1,997) |
| Net\tissuances | $282 | $(349) |

(1)	The	proceeds	of	the	commercial	paper	issuances	were	used	primarily	for	short-term	working	capital	needs.

On	December	3,	2018,	Aon	Corporation	issued	$350	million	4.50%	Senior	Notes	due	December	2028.	The	Company	used	the	proceeds	for	general	corporate purposes.

On	March	8,	2018	the	Company's	CAD	375	million	($291	million	at	March	8,	2018	Exchange	Rates)	4.76%	Senior	Notes	due	March	2018	issued	by	a	Canadian subsidiary	of	Aon	Corporation	matured	and	was	repaid	in	full.

# Other	Liquidity	Matters

# Distributable	Reserves

As	a	company	incorporated	in	England	and	Wales,	we	are	required	under	U.K.	law	to	have	available	"distributable	reserves"	to	make	share	repurchases	or	pay dividends	to	shareholders.	Distributable	reserves	may	be	created	through	the	earnings	of	the	U.K.	parent	company	and,	among	other	methods,	through	a	reduction	in share	capital	approved	by	the	courts	of	England	and	Wales.	Distributable	reserves	are	not	linked	to	a	U.S.	GAAP	reported	amount	(e.g.,	retained	earnings).	As	of December	31,	2018	and	2017,	we	had	distributable	reserves	in	excess	of	$2.2	billion	and	$1.2	billion,	respectively.	We	believe	that	we	will	have	sufficient	distributable reserves	to	fund	shareholder	dividends	and	make	share	repurchases	for	the	foreseeable	future.

# Credit	Facilities

We	expect	cash	generated	by	operations	for	2018	to	be	sufficient	to	service	our	debt	and	contractual	obligations,	finance	capital	expenditures,	continue	purchases	of shares	under	the	Repurchase	Program,	and	continue	to	pay	dividends	to	our	shareholders.		Although	cash	from	operations	is	expected	to	be	sufficient	to	service	these activities,	 we	 have	 the	 ability	 to	 access	 the	 commercial	 paper	 markets	 or	 borrow	 under	 our	 credit	 facilities	 to	 accommodate	 any	 timing	 differences	 in	 cash flows.	Additionally,	under	current	market	conditions,	we	believe	that	we	could	access	capital	markets	to	obtain	debt	financing	for	longer-term	funding,	if	needed.

As	of	December	31,	2018,	we	had	two	primary	committed	credit	facilities	outstanding:	our	$900	million	multi-currency	U.S.	credit	facility	expiring	in	February 2021	(the	"2021	Facility")	and	our	$400	million	multi-currency	U.S.	credit	facility	expiring	in	October	2022	(the	"2022	Facility").	On	February	2,	2019,	we	extended	the 2021	Facility	by	one	year,	and	it	will	now	expire	in	February	2022.

Each	of	these	facilities	includes	customary	representations,	warranties,	and	covenants,	including	financial	covenants	that	require	us	to	maintain	specified	ratios	of adjusted	consolidated	earnings	before	interest,	taxes,	depreciation,	and	amortization	("EBITDA")	to	consolidated	interest	expense	and	consolidated	debt	to	adjusted consolidated	EBITDA,	in	each	case,	tested	quarterly.	At	December	31,	2018,	we	did	not	have	borrowings	under	either	the	2021	Facility	or	the	2022	Facility,	and	we were	in	compliance	with	all	other	covenants	contained	therein	during	the	twelve	months	ended	December	31,	2018.

# Shelf	Registration	Statement

On	September	25,	2018,	we	filed	a	shelf	registration	statement	with	the	SEC,	registering	the	offer	and	sale	from	time	to	time	of	an	indeterminate	amount	of,	among other	securities,	debt	securities,	preference	shares,	Class	A	Ordinary	Shares,	and	convertible	securities.	Our	ability	to	access	the	market	as	a	source	of	liquidity	is dependent	on	investor	demand,	market	conditions,	and	other	factors.

# Rating	Agency	Ratings

The	major	rating	agencies'	ratings	of	our	debt	at	February	19,	2019	appear	in	the	table	below.

A	downgrade	in	the	credit	ratings	of	our	senior	debt	and	commercial	paper	could	increase	our	borrowing	costs,	reduce	or	eliminate	our	access	to	debt	capital,	reduce our	financial	flexibility,	or	restrict	our	access	to	the	commercial	paper	market	altogether,	and/or	impact	future	pension	contribution	requirements.

# Guarantees	in	Connection	with	the	Sale	of	the	Divested	Business

In	connection	with	the	sale	of	the	Divested	Business,	we	guaranteed	future	operating	lease	commitments	related	to	certain	facilities	assumed	by	the	Buyer.	We	are obligated	to	perform	under	the	guarantees	if	the	Divested	Business	defaults	on	the	leases	at	any	time	during	the	remainder	of	the	lease	agreements,	which	expire	on various	dates	through	2024.	As	of	December	31,	2018,	the	undiscounted	maximum	potential	future	payments	under	the	lease	guarantee	were	$85	million,	with	an estimated	fair	value	of	$17	million.	No	cash	payments	were	made	in	connection	to	the	lease	commitments	during	the	year	ended	December	31,	2018.

Additionally,	we	are	subject	to	performance	guarantee	requirements	under	certain	client	arrangements	that	were	assumed	by	the	Buyer.	Should	the	Divested Business	fail	to	perform	as	required	by	the	terms	of	the	arrangements,	we	would	be	required	to	fulfill	the	remaining	contract	terms,	which	expire	on	various	dates through	2023.	As	of	December	31,	2018,	the	undiscounted	maximum	potential	future	payments	under	the	performance	guarantees	were	$188	million,	with	an	estimated fair	value	of	$1	million.	No	cash	payments	were	made	in	connection	to	the	performance	guarantees	during	the	year	ended	December	31,	2018.

# Letters	of	Credit	and	Other	Guarantees

We	have	entered	into	a	number	of	arrangements	whereby	our	performance	on	certain	obligations	is	guaranteed	by	a	third	party	through	the	issuance	of	a	letter	of credit	("LOCs").	We	had	total	LOCs	outstanding	of	approximately	$83	million	at	December	31,	2018,	compared	to	$96	million	at	December	31,	2017.	These	LOCs cover	 the	 beneficiaries	 related	 to	 certain	 of	 our	 U.S.	 and	 Canadian	 non-qualified	 pension	 plan	 schemes	 and	 secure	 deductible	 retentions	 for	 our	 own	 workers' compensation	program.	We	also	have	obtained	LOCs	to	cover	contingent	payments	for	taxes	and	other	business	obligations	to	third	parties,	and	other	guarantees	for miscellaneous	purposes	at	our	international	subsidiaries.

The	Company	has	certain	contractual	contingent	guarantees	for	premium	payments	owed	by	clients	to	certain	insurance	companies.	The	maximum	exposure	with respect	to	such	contractual	contingent	guarantees	was	approximately	$103	million	at	December	31,	2018,	compared	to	$95	million	at	December	31,	2017.

# Off-Balance	Sheet	Arrangements

Apart	 from	 commitments,	 guarantees,	 and	 contingencies,	 as	 disclosed	 herein	 and	 Note	 17	 "Claims,	 Lawsuits,	 and	 Other	 Contingencies"	 of	 the	 Notes	 to Consolidated	Financial	Statements	in	Part	II,	Item	8	of	this	report,	the	Company	had	no	off-balance	sheet	arrangements	that	have,	or	are	reasonably	likely	to	have,	a current	or	future	material	effect	on	the	Company's	financial	condition,	results	of	operations,	or	liquidity.	Our	cash	flows	from	operations,	borrowing	availability,	and overall	liquidity	are	subject	to	risks	and	uncertainties.	See	"Information	Concerning	Forward-Looking	Statements"	below.

# Contractual	Obligations

Summarized	in	the	table	below	are	our	contractual	obligations	and	commitments	as	of	December	31,	2018.	Payments	by	year	due	are	estimated	as	follows	(in millions):

|  | 2019 | 2020-2021 | 2022-2023 | After	2023 | Total |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Principal\tpayments\ton\tdebt | $251 | $1,000 | $— | $5,095 | $6,346 |
| Interest\tpayments\ton\tdebt | 275 | 514 | 467 | 2,220 | 3,476 |
| Operating\tleases | 303 | 474 | 330 | 472 | 1,579 |
| Pension\tand\tother\tpostretirement\tbenefit\tplans | 150 | 270 | 298 | 314 | 1,032 |
| Purchase\tobligations | 179 | 132 | 24 | 5 | 340 |
| Total | $1,158 | $2,390 | $1,119 | $8,106 | $12,773 |

Pension	and	other	postretirement	benefit	plan	obligations	include	estimates	of	our	minimum	funding	requirements	pursuant	to	the	Employee	Retirement	Income Security	Act	and	other	regulations,	as	well	as	minimum	funding	requirements	agreed	with	the	trustees	of	our	U.K.	pension	plans.	Additional	amounts	may	be	agreed	to with,	or	required	by,	the	U.K.	pension	plan	trustees.	Nonqualified	pension	and	other	postretirement	benefit	obligations	are	based	on	estimated	future	benefit	payments. We	may	make	additional	discretionary	contributions.

In	2017,	our	principal	U.K.	subsidiary	agreed	with	the	trustees	of	one	of	the	U.K.	plans	to	contribute	£44	million	($59	million	at	December	31,	2017	exchange rates)	through	2019	which	is	estimated	to	bring	the	plan	to	100%	funded	basis.	Contributions	were	based	on	the	2016	valuation	and	no	further	contributions	are forecasted	after	2019.	The	trustees	of	the	plan	have	certain	rights	to	request	that	our	U.K.	subsidiary	advance	an	amount	equal	to	an	actuarially	determined	winding-up deficit.	As	of	December	31,	2018,	the	estimated	winding-up	deficit	was	£84	million	($106	million	at	December	31,	2018	exchange	rates).	The	trustees	of	the	plan	have accepted	in	practice	the	agreed-upon	schedule	of	contributions	detailed	above	and	have	not	requested	the	winding-up	deficit	be	paid.

Purchase	obligations	are	defined	as	agreements	to	purchase	goods	and	services	that	are	enforceable	and	legally	binding	on	us,	and	that	specifies	all	significant	terms, including	the	goods	to	be	purchased	or	services	to	be	rendered,	the	price	at	which	the	goods	or	services	are	to	be	rendered,	and	the	timing	of	the	transactions.	Most	of	our purchase	obligations	are	related	to	purchases	of	information	technology	services	or	other	service	contracts.	Purchase	obligations	exclude	$279	million	of	liabilities	for uncertain	tax	positions	due	to	our	inability	to	reasonably	estimate	the	period(s)	when	potential	cash	settlements	will	be	made.

# CRITICAL	ACCOUNTING	POLICIES	AND	ESTIMATES

Our	 Financial	 Statements	 have	 been	 prepared	 in	 accordance	 with	 U.S.	 GAAP.	To	 prepare	 these	 financial	 statements,	 we	 make	 estimates,	 assumptions,	 and judgments	that	affect	what	we	report	as	our	assets	and	liabilities,	what	we	disclose	as	contingent	assets	and	liabilities	at	the	date	of	the	Financial	Statements,	and	the reported	amounts	of	revenues	and	expenses	during	the	periods	presented.

In	accordance	with	our	policies,	we	regularly	evaluate	our	estimates,	assumptions,	and	judgments,	including,	but	not	limited	to,	those	concerning	restructuring, revenue	recognition,	pensions,	goodwill	and	other	intangible	assets,	contingencies,	share-based	payments,	and	income	taxes,	and	base	our	estimates,	assumptions,	and judgments	on	our	historical	experience	and	on	factors	we	believe	reasonable	under	the	circumstances.	The	results	involve	judgments	about	the	carrying	values	of	assets and	liabilities	not	readily	apparent	from	other	sources.	If	our	assumptions	or	conditions	change,	the	actual	results	we	report	may	differ	from	these	estimates.	We	believe the	following	critical	accounting	policies	affect	the	more	significant	estimates,	assumptions,	and	judgments	we	use	to	prepare	these	Financial	Statements.

# Revenue	Recognition

The	Company	recognizes	revenue	when	control	of	the	promised	services	is	transferred	to	the	customer	in	the	amount	that	best	reflects	the	consideration	to	which	the Company	expects	to	be	entitled	in	exchange	for	those	services.	For	arrangements	where	control	is	transferred	over	time,	an	input	or	output	method	is	applied	that represents	a	faithful	depiction	of	the	progress	towards	completion	of	the	performance	obligation.	For	arrangements	that	include	variable	consideration,	the	Company assesses	whether	any	amounts	should	be	constrained.	For	arrangements	that	include	multiple	performance	obligations,	the	Company	allocates	consideration	based	on their	relative	fair	values.

Costs	incurred	by	the	Company	in	obtaining	a	contract	are	capitalized	and	amortized	on	a	systematic	basis	that	is	consistent	with	the	transfer	of	control	of	the services	to	which	the	asset	relates,	considering	anticipated	renewals	when	applicable.	Certain	contract	related	costs,	including	pre-placement	brokerage	costs,	are capitalized	as	a	cost	to	fulfill	and	are	amortized	on	a	systematic	basis	consistent	with	the	transfer	of	control	of	the	services	to	which	the	asset	relates,	which	is	generally less	than	one	year.

Commercial	Risk	Solutions	includes	retail	brokerage,	cyber	solutions,	global	risk	consulting,	and	captives.	Revenue	primarily	includes	insurance	commissions	and fees	for	services	rendered.	Revenue	is	predominantly	recognized	at	a	point	 in	 time	upon	 the	effective	date	of	 the	underlying	policy,	or	for	a	 limited	number	of arrangements,	over	the	term	of	the	arrangement	using	output	measures	to	depict	the	transfer	of	control	of	the	services	to	customers	in	an	amount	that	reflects	the consideration	to	which	the	Company	expects	to	be	entitled	in	exchange	for	those	services.	For	arrangements	recognized	over	time,	various	output	measures,	including units	transferred	and	time	elapsed,	are	utilized	to	provide	a	faithful	depiction	of	the	progress	towards	completion	of	the	performance	obligation.	Revenue	is	recorded	net of	allowances	for	estimated	policy	cancellations,	which	are	determined	based	on	an	evaluation	of	historical	and	current	cancellation	data.	Commissions	and	fees	for brokerage	services	may	be	invoiced	near	the	effective	date	of	the	underlying	policy	or	over	the	term	of	the	arrangement	in	installments	during	the	policy	period.

Reinsurance	Solutions	includes	treaty	and	facultative	reinsurance	brokerage	and	capital	markets.	Revenue	primarily	includes	reinsurance	commissions	and	fees	for services	rendered.	Revenue	is	predominantly	recognized	at	a	point	in	time	upon	the	effective	date	of	the	underlying	policy	(or	policies),	or	for	a	limited	number	of arrangements,	over	the	term	of	the	arrangement	using	output	measures	to	depict	the	transfer	of	control	of	the	services	to	customers	in	an	amount	that	reflects	the consideration	to	which	the	Company	expects	to	be	entitled	in	exchange	for	those	services.	For	arrangements	recognized	over	time,	various	output	measures,	including units	delivered	and	time	elapsed,	are	utilized	to	provide	a	faithful	depiction	of	the	progress	towards	completion	of	the	performance	obligation.	Commissions	and	fees	for brokerage	services	may	be	invoiced	at	the	inception	of	the	reinsurance	period	for	certain	reinsurance	brokerage,	or	more	commonly,	over	the	term	of	the	arrangement	in installments	based	on	deposit	or	minimum	premiums	for	most	treaty	reinsurance	arrangements.

Retirement	Solutions	includes	core	retirement,	investment	consulting,	and	talent,	rewards	&	performance.	Revenue	consists	primarily	of	fees	paid	by	customers	for consulting	services,	such	as	risk	management	strategies,	health	and	benefits,	and	human	capital	consulting	services.	Revenue	recognized	for	these	arrangements	is predominantly	recognized	over	the	term	of	the	arrangement	using	input	or	output	measures	to	depict	the	transfer	of	control	of	the	services	to	customers	in	an	amount	that reflects	the	consideration	to	which	the	Company	expects	to	be	entitled	in	exchange	for	those	services,	or	for	certain	arrangements,	at	a	point	in	time	upon	completion	of the	services.	For	consulting	arrangements	recognized	over	time,	revenue	will	be	recognized	based	on	a	measure	of	progress	that	depicts	the	transfer	of	control	of	the services	to	the	customer,	utilizing	an	appropriate	input	or	output	measure	to	provide	a	reasonable	assessment	of	the	progress	towards	completion	of	the	performance obligation	including	units	delivered	or	time	elapsed.	Fees	paid	by	customers	for	consulting	services	are	typically	charged	on	an	hourly,	project	or	fixed-fee	basis,	and revenue	for	 these	arrangements	 is	 typically	recognized	based	on	 time	 incurred,	days	elapsed,	or	reports	delivered.	Revenue	from	 time-and-materials	or	cost-plus arrangements	are	recognized	as	services	are	performed	using	input	or	output	measures	to	provide	a	reasonable	assessment	of	the	progress	towards	completion	of	the performance	obligation	including	hours	worked,	and	revenue	for	these	arrangements	is	typically	recognized	based	on	time	and	materials	incurred.	Reimbursements received	for	out-of-pocket	expenses	are	recorded	as	a	component	of	revenue.	Payment	terms	vary	but	are	typically	over	the	contract	term	in	installments.

Health	Solutions includes	health	and	benefits	brokerage	and	health	care	exchanges.	Revenue	primarily	 includes	 insurance	commissions	and	fees	for	services rendered.	For	brokerage	commissions,	revenue	is	predominantly	recognized	at	the	effective	date	of	the	underlying	policy	(or	policies),	or	for	a	limited	number	of arrangements,	over	the	term	of	the	arrangement	to	depict	the	transfer	of	control	of	the	services	to	customers	in	an	amount	that	reflects	the	consideration	to	which	the Company	expects	to	be	entitled	in	exchange	for	those	services	using	input	or	output	measures,	including	units	delivered	or	time	elapsed,	to	provide	a	faithful	depiction	of the	progress	towards	completion	of	the	performance	obligation.	Revenue	from	health	care	exchange	arrangements	are	typically	recognized	upon	successful	enrollment of	participants,	net	of	a	reserve	for	estimated	cancellations.	Commissions	and	fees	for	brokerage	services	may	be	invoiced	at	the	effective	date	of	the	underlying	policy or	over	 the	 term	of	 the	arrangement	 in	 installments	during	 the	policy	period.	Payment	 terms	for	other	services	vary	but	are	 typically	over	 the	contract	 term	 in installments.

Data	&	Analytic	Services	includes	Affinity,	Aon	InPoint,	and	ReView.		Revenue	consists	primarily	of	fees	for	services	rendered	and	is	generally	recognized	over the	term	of	the	arrangement	to	depict	the	transfer	of	control	of	the	services	to	customers	in	an	amount	that	reflects	the	consideration	to	which	the	Company	expects	to	be entitled	in	exchange	for	those	services.	Payment	terms	vary	but	are	typically	over	the	contract	term	in	installments.	For	Data	&	Analytic	Services	arrangements recognized	over	time,	revenue	will	be	recognized	based	on	a	measure	of	progress	that	depicts	the	transfer	of	control	of	the	services	to	the	customer,	utilizing	an appropriate	input	or	output	measure	to	provide	a	faithful	depiction	of	the	progress	towards	completion	of	the	performance	obligation,	including	units	delivered	or	time elapsed.	Input	and	output	measures	utilized	vary	based	on	the	arrangement	but	typically	include	reports	provided	or	days	elapsed.

# Restructuring

# Workforce	reduction	costs

The	method	used	to	account	for	workforce	reduction	costs	depends	on	whether	the	costs	result	from	an	ongoing	severance	plan	or	are	one-time	costs.	We	account for	relevant	expenses	as	severance	costs	when	we	have	an	established	severance	policy,	statutory	requirements	dictate	the	severance	amounts,	or	we	have	an	established pattern	of	paying	by	a	specific	formula.	We	recognize	these	costs	when	the	likelihood	of	future	settlement	is	probable	and	the	amount	of	the	related	benefit	is	reasonably estimable,	or	on	a	straight-line	basis	over	the	remaining	service	period,	if	applicable.

We	estimate	our	one-time	workforce	reduction	costs	related	to	exit	and	disposal	activities	not	resulting	from	an	ongoing	severance	plan	based	on	the	benefits available	to	the	employees	being	terminated.	We	recognize	these	costs	when	we	identify	the	specific	classification	(or	functions)	and	locations	of	the	employees	being terminated,	notify	the	employees	who	might	be	included	in	the	termination,	and	expect	to	terminate	employees	within	the	legally	required	notification	period.	When employees	are	receiving	incentives	to	stay	beyond	the	legally	required	notification	period,	we	record	the	cost	of	their	severance	over	the	remaining	service	period.

# Lease	consolidation	costs

Where	we	have	provided	notice	of	cancellation	pursuant	to	a	lease	agreement	or	abandoned	space	and	have	no	intention	of	reoccupying	it,	we	recognize	a	loss.	The loss	reflects	our	best	estimate	of	the	net	present	value	of	the	future	cash	flows	associated	with	the	lease	at	the	date	we	provide	notice	of	cancellation	in	accordance	with contractual	terms,	vacate	the	property,	or	sign	a	sublease	arrangement.	To	determine	the	loss,	we	estimate	sublease	income	based	on	current	market	quotes	for	similar properties.	When	we	finalize	definitive	agreements	with	the	sublessee,	we	adjust	our	sublease	losses	for	actual	outcomes.

# Fair	value	concepts	of	one-time	workforce	reduction	costs	and	lease	losses

Accounting	guidance	requires	that	our	exit	and	disposal	accruals	reflect	the	fair	value	of	the	liability.	Where	material,	we	discount	the	lease	loss	calculations	to arrive	at	their	net	present	value.	Most	workforce	reductions	happen	over	a	short	span	of	time,	so	no	discounting	is	necessary.

For	the	remaining	lease	term,	we	decrease	the	liability	for	payments	and	increase	the	liability	for	accretion	of	the	discount,	if	material.	The	discount	reflects	our incremental	borrowing	rate,	which	matches	the	lifetime	of	the	liability.	Significant	changes	in	the	discount	rate	selected	or	the	estimations	of	sublease	income	in	the	case of	leases	could	impact	the	amounts	recorded.

# Asset	impairments

Asset	impairments	relate	to	fixed	assets	and	are	accounted	for	in	the	period	when	they	become	known.	Furthermore,	we	record	impairments	by	reducing	the	book value	to	the	net	present	value	of	future	cash	flows	(in	situations	where	the	asset	had	an	identifiable	cash	flow	stream)	or	accelerating	the	depreciation	to	reflect	the	revised useful	life.	Asset	impairments	are	included	in	Depreciation	of	fixed	assets	in	the	Consolidated	Statements	of	Income.

# Other	associated	costs	of	exit	and	disposal	activities

We	recognize	other	costs	associated	with	exit	and	disposal	activities	as	they	are	incurred,	including	separation	costs,	moving	costs	and	consulting	and	legal	fees.

# Pensions

We	sponsor	defined	benefit	pension	plans	throughout	the	world.	Our	most	significant	plans	are	located	in	the	U.S.,	the	U.K.,	the	Netherlands,	and	Canada,	which are	closed	to	new	entrants.	We	have	ceased	crediting	future	benefits	relating	to	salary	and	services	for	our	U.S.,	U.K.,	Netherlands,	and	Canadian	plans	to	the	extent statutorily	permitted.

The	service	cost	component	of	net	periodic	benefit	cost	is	reported	in	Compensation	and	benefits	and	all	other	components	are	reported	in	Other	income	(expense). We	used	a	full-yield	curve	approach	in	the	estimation	of	the	service	and	interest	cost

components	of	net	periodic	pension	and	postretirement	benefit	cost	for	our	major	pension	and	other	postretirement	benefit	plans;	this	was	obtained	by	applying	the specific	spot	rates	along	the	yield	curve	used	in	the	determination	of	the	benefit	obligation	to	the	relevant	projected	cash	flows.

# Recognition	of	gains	and	losses	and	prior	service

Certain	changes	in	the	value	of	the	obligation	and	in	the	value	of	plan	assets,	which	may	occur	due	to	various	factors	such	as	changes	in	the	discount	rate	and actuarial	assumptions,	actual	demographic	experience,	and/or	plan	asset	performance	are	not	immediately	recognized	in	net	income.	Such	changes	are	recognized	in Other	comprehensive	income	and	are	amortized	into	net	income	as	part	of	the	net	periodic	benefit	cost.

Unrecognized	gains	and	losses	that	have	been	deferred	in	Other	comprehensive	income,	as	previously	described,	are	amortized	into	expense	as	a	component	of periodic	pension	expense	based	on	the	average	life	expectancy	of	the	U.S.,	U.K.,	Netherlands,	and	Canada	plan	members.	We	amortize	any	prior	service	expense	or credits	that	arise	as	a	result	of	plan	changes	over	a	period	consistent	with	the	amortization	of	gains	and	losses.

As	of	December	31,	2018,	our	pension	plans	have	deferred	losses	that	have	not	yet	been	recognized	through	income	in	the	Consolidated	Financial	Statements.	We amortize	unrecognized	actuarial	losses	outside	of	a	corridor,	which	is	defined	as	10%	of	the	greater	of	market-related	value	of	plan	assets	or	projected	benefit	obligation. To	the	extent	not	offset	by	future	gains,	incremental	amortization	as	calculated	above	will	continue	to	affect	future	pension	expense	similarly	until	fully	amortized.

The	following	table	discloses	our	unrecognized	actuarial	gains	and	losses,	the	number	of	years	over	which	we	are	amortizing	the	experience	loss,	and	the	estimated 2019	amortization	of	loss	by	country	(millions,	except	amortization	period):

|  | U.K. | U.S. | Other |
| :--- | :--- | :--- | :--- |
| Unrecognized\tactuarial\tgains\tand\tlosses | $1,136 | $1,708 | $433 |
| Amortization\tperiod | 8\t-\t28 | 7\t-\t23 | 13\t-\t40 |
| Estimated\t2019\tamortization\tof\tloss | $30 | $55 | $12 |

The	unrecognized	prior	service	cost	(credit)	at	December	31,	2018	was	$3	million,	$30	million,	and	$(7)	million	for	the	U.S.,	U.K.	and	other	plans,	respectively.

For	the	U.S.	pension	plans,	we	use	a	market-related	valuation	of	assets	approach	to	determine	the	expected	return	on	assets,	which	is	a	component	of	net	periodic benefit	cost	recognized	in	the	Consolidated	Statements	of	Income.	This	approach	recognizes	20%	of	any	gains	or	losses	in	the	current	year's	value	of	market-related assets,	with	the	remaining	80%	spread	over	the	next	four	years.	As	this	approach	recognizes	gains	or	losses	over	a	five-year	period,	the	future	value	of	assets	and therefore,	our	net	periodic	benefit	cost	will	be	impacted	as	previously	deferred	gains	or	losses	are	recorded.	As	of	December	31,	2018,	the	market-related	value	of	assets was	$2.0	billion.	We	do	not	use	the	market-related	valuation	approach	to	determine	the	funded	status	of	the	U.S.	plans	recorded	in	the	Consolidated	Statements	of Financial	Position.	Instead,	we	record	and	present	the	funded	status	in	the	Consolidated	Statements	of	Financial	Position	based	on	the	fair	value	of	the	plan	assets.	As	of December	31,	2018,	the	fair	value	of	plan	assets	was	$1.8	billion.

Our	non-U.S.	plans	use	fair	value	to	determine	expected	return	on	assets.

# Rate	of	return	on	plan	assets	and	asset	allocation

The	following	table	summarizes	the	expected	long-term	rate	of	return	on	plan	assets	for	future	pension	expense	as	of	December	31,	2018:

|  | U.K. | U.S. | Other |
| :--- | :--- | :--- | :--- |
| Expected\treturn | 3.64% | 7.05% | 2.50\t-\t4.10% |

In	determining	the	expected	rate	of	return	for	the	plan	assets,	we	analyze	investment-community	forecasts	and	current	market	conditions	to	develop	expected	returns for	each	of	the	asset	classes	used	by	the	plans.	In	particular,	we	surveyed	multiple	third-party	financial	institutions	and	consultants	to	obtain	long-term	expected	returns on	each	asset	class,	considered	historical	performance	data	by	asset	class	over	long	periods,	and	weighted	the	expected	returns	for	each	asset	class	by	target	asset allocations	of	the	plans.

The	U.S.	pension	plan	asset	allocation	is	based	on	approved	allocations	following	adopted	investment	guidelines.	The	investment	policy	for	U.K.	and	other	non- U.S.	pension	plans	is	generally	determined	by	the	plans'	trustees.	Because	there	are	several	pension	plans	maintained	in	the	U.K.	and	other	non-U.S.	categories,	our target	allocation	presents	a	range	of	the	target	allocation	of	each	plan.	Target	allocations	are	subject	to	change.

# Impact	of	changing	economic	assumptions

Changes	in	the	discount	rate	and	expected	return	on	assets	can	have	a	material	impact	on	pension	obligations	and	pension	expense.

Holding	all	other	assumptions	constant,	the	following	table	reflects	what	a	25	basis	point	("bps")	increase	and	decrease	in	our	estimated	discount	rate	would	have	on our	projected	benefit	obligation	at	December	31,	2018	(in	millions):

| Increase	(decrease)	in	projected	benefit	obligation	^(1) | Increase | Decrease |
| :--- | :--- | :--- |
| U.K.\tplans | $(158) | $168 |
| U.S.\tplans | (80) | 84 |
| Other\tplans | (70) | 79 |

(1) Increases	to	the	projected	benefit	obligation	reflect	increases	to	our	pension	obligations,	while	decreases	in	the	projected	benefit	obligation	are	recoveries	toward	fully-funded	status.	A	change	in the	discount	rate	has	an	inverse	relationship	to	the	projected	benefit	obligation.

Holding	all	other	assumptions	constant,	the	following	table	reflects	what	a	25	bps	increase	and	decrease	in	our	discount	rate	would	have	on	our	estimated	2019 pension	expense	(in	millions):

| Increase	(decrease)	in	expense | Increase | Decrease |
| :--- | :--- | :--- |
| U.K.\tplans | $(2) | $1 |
| U.S.\tplans | 1 | (1) |
| Other\tplans | (1) | 1 |

Holding	all	other	assumptions	constant,	the	following	table	reflects	what	a	25	bps	increase	and	decrease	in	our	long-term	rate	of	return	on	plan	assets	would	have	on our	estimated	2019	pension	expense	(in	millions):

| Increase	(decrease)	in	expense | Increase | Decrease |
| :--- | :--- | :--- |
| U.K.\tplans | $(13) | $13 |
| U.S.\tplans | (5) | 5 |
| Other\tplans | (2) | 2 |

# Estimated	future	contributions

We	estimate	cash	contributions	of	approximately	$145	million	to	our	pension	plans	in	2019	as	compared	with	cash	contributions	of	$252	million	in	2018,	which includes	our	acceleration	of	contributions	to	the	qualified	U.S.	pension	plan.

# Goodwill	and	Other	Intangible	Assets

Goodwill	represents	the	excess	of	cost	over	the	fair	market	value	of	the	net	assets	acquired.	We	classify	our	intangible	assets	acquired	as	either	tradenames, customer-related	and	contract-based,	or	technology	and	other.

Goodwill	is	not	amortized,	but	rather	tested	for	impairment	at	least	annually	in	the	fourth	quarter.	We	test	more	frequently	if	there	are	indicators	of	impairment	or whenever	business	circumstances	suggest	that	the	carrying	value	of	goodwill	may	not	be	recoverable.	These	indicators	may	include	a	sustained	significant	decline	in	our share	price	and	market	capitalization,	a	decline	in	our	expected	future	cash	flows,	or	a	significant	adverse	change	in	legal	factors	or	in	the	business	climate,	among others.	No	events	occurred	during	2018	that	indicate	the	existence	of	an	impairment	with	respect	to	our	reported	goodwill.

We	perform	impairment	reviews	at	the	reporting	unit	level.	A	reporting	unit	is	an	operating	segment	or	one	level	below	an	operating	segment	(referred	to	as	a "component").	A	component	of	an	operating	segment	is	a	reporting	unit	if	the	component	constitutes	a	business	for	which	discrete	financial	information	is	available	and segment	management	regularly	reviews	the	operating	results	of	that	component.	An	operating	segment	shall	be	deemed	to	be	a	reporting	unit	if	all	of	its	components	are similar,	if	none	of	its	components	are	a	reporting	unit,	or	if	the	segment	comprises	only	a	single	component.

When	evaluating	these	assets	for	impairment,	we	may	first	perform	a	qualitative	assessment	to	determine	whether	it	is	more	likely	than	not	that	a	reporting	unit	is impaired.	If	we	do	not	perform	a	qualitative	assessment,	or	if	we	determine	that	it	is	not	more	likely	than	not	that	the	fair	value	of	the	reporting	unit	exceeds	its	carrying amount,	then	the	goodwill	impairment	test	becomes	a	two-step	analysis.	Step	1	requires	 the	fair	value	of	each	reporting	unit	 to	be	compared	 to	 its	book	value. Management	must	apply	judgment	in	determining	the	estimated	fair	value	of	the	reporting	units.	If	the	fair	value	of	a	reporting	unit	is	determined	to	be	greater	than	the carrying	value	of	the	reporting	unit,	goodwill	is	deemed	not	to	be	impaired	and	no	further	testing	is	necessary.	If	the	fair	value	of	a	reporting	unit	is	less	than	the	carrying value,	we	perform	Step	2.	Step	2	uses	the	calculated	fair	value	of	the	reporting	unit	to	perform	a	hypothetical	purchase	price	allocation	to	the	fair	value	of	the	assets	and liabilities	of	the	reporting	unit.	The	difference	between	the	fair	value	of	the	reporting	unit	calculated	in	Step	1	and	the	fair	value	of	the	underlying	assets	and	liabilities	of the	reporting	unit	is	the	implied	fair	value	of	the	reporting	unit's	goodwill.	A	charge	is	recorded	in	the	financial	statements	if	the	carrying	value	of	the	reporting	unit's goodwill	is	greater	than	its	implied	fair	value.

In	determining	the	fair	value	of	our	reporting	units,	we	use	a	discounted	cash	flow	("DCF")	model	based	on	our	most	current	forecasts.	We	discount	the	related	cash flow	forecasts	using	the	weighted-average	cost	of	capital	method	at	the	date	of	evaluation.	Preparation	of	forecasts	and	selection	of	the	discount	rate	for	use	in	the	DCF model	involve	significant	judgments,	and	changes	in	these	estimates	could	affect	the	estimated	fair	value	of	one	or	more	of	our	reporting	units	and	could	result	in	a goodwill	impairment	charge	in	a	future	period.	We	also	use	market	multiples	which	are	obtained	from	quoted	prices	of	comparable	companies	to	corroborate	our	DCF model	results.	The	combined	estimated	fair	value	of	our	reporting	units	from	our	DCF	model	often	results	in	a	premium	over	our	market	capitalization,	commonly referred	to	as	a	control	premium.	We	believe	the	implied	control	premium	determined	by	our	impairment	analysis	is	reasonable	based	upon	historic	data	of	premiums paid	on	actual	transactions	within	our	industry.	Based	on	tests	performed	in	both	2018	and	2017,	there	was	no	indication	of	goodwill	impairment,	and	no	further	testing was	required.

We	review	intangible	assets	that	are	being	amortized	for	impairment	whenever	events	or	changes	in	circumstance	indicate	that	their	carrying	amount	may	not	be recoverable.	There	were	no	indications	that	the	carrying	values	of	amortizable	intangible	assets	were	impaired	as	of	December	31,	2018.	If	we	are	required	to	record impairment	charges	in	the	future,	they	could	materially	impact	our	results	of	operations.

# Contingencies

We	define	a	contingency	as	an	existing	condition	that	involves	a	degree	of	uncertainty	as	to	a	possible	gain	or	loss	that	will	ultimately	be	resolved	when	one	or	more future	events	occur	or	fail	to	occur.	Under	U.S.	GAAP,	we	are	required	to	establish	reserves	for	loss	contingencies	when	the	loss	is	probable	and	we	can	reasonably estimate	its	financial	impact.	We	are	required	to	assess	the	likelihood	of	material	adverse	judgments	or	outcomes,	as	well	as	potential	ranges	or	probability	of	losses.	We determine	the	amount	of	reserves	required,	if	any,	for	contingencies	after	carefully	analyzing	each	individual	item.	The	required	reserves	may	change	due	to	new developments	in	each	issue.	We	do	not	recognize	gain	contingencies	until	the	contingency	is	resolved	and	amounts	due	are	probable	of	collection.

# Share-Based	Payments

Share-based	compensation	expense	is	measured	based	on	the	estimated	grant	date	fair	value	and	recognized	over	the	requisite	service	period	for	awards	that	we ultimately	expect	to	vest.	We	estimate	forfeitures	at	the	time	of	grant	based	on	our	actual	experience	to	date	and	revise	our	estimates,	if	necessary,	in	subsequent	periods if	actual	forfeitures	differ	from	those	estimates.

# Restricted	Share	Units

Restricted	share	units	("RSUs")	are	service-based	awards	for	which	we	recognize	the	associated	compensation	cost	on	a	straight-line	basis	over	the	requisite	service period.	We	estimate	the	fair	value	of	the	awards	based	on	the	market	price	of	the	underlying	share	on	the	date	of	grant,	reduced	by	the	present	value	of	estimated dividends	foregone	during	the	vesting	period	where	applicable.

# Performance	Share	Awards

Performance	share	awards	("PSAs")	are	performance-based	awards	for	which	vesting	is	dependent	on	the	achievement	of	certain	objectives.	Such	objectives	may be	made	on	a	personal,	group	or	company	level.	We	estimate	the	fair	value	of	the	awards	based	on	the	market	price	of	the	underlying	share	on	the	date	of	grant,	reduced by	the	present	value	of	estimated	dividends	foregone	during	the	vesting	period.

Compensation	expense	is	recognized	over	the	performance	period.	The	number	of	shares	issued	on	the	vesting	date	will	vary	depending	on	the	actual	performance objectives	achieved.	We	make	assessments	of	future	performance	using	subjective	estimates,	such	as	long-term	plans.	As	a	result,	changes	in	the	underlying	assumptions could	have	a	material	impact	on	the	compensation	expense	recognized.

The	largest	plan	is	the	Leadership	Performance	Plan	("LPP"),	which	has	a	three-year	performance	period.	As	the	percent	of	expected	performance	increases	or decreases,	the	potential	change	in	expense	can	go	from	0%	to	200%	of	the	targeted	total	expense.	The	2016	to	2018	performance	period	ended	on	December	31,	2018, the	2015	to	2017	performance	period	ended	on	December	31,	2017	and	the	2014	to	2016	performance	period	ended	on	December	31,	2016.	The	LPP	currently	has	two open	performance	periods:	2017	to	2019	and	2018	to	2020.	A	10%	upward	adjustment	in	our	estimated	performance	achievement	percentage	for	both	open	performance periods	would	have	increased	our	2018	expense	by	approximately	$2.1	million,	while	a	10%	downward	adjustment	would	have	decreased	our	expense	by	approximately $6.0	million.

# Income	Taxes

We	earn	income	in	numerous	countries	and	this	income	is	subject	to	the	laws	of	taxing	jurisdictions	within	those	countries.

The	carrying	values	of	deferred	income	tax	assets	and	liabilities	reflect	the	application	of	our	income	tax	accounting	policies	and	are	based	on	management's assumptions	and	estimates	about	future	operating	results	and	levels	of	taxable	income,	and	judgments	regarding	the	interpretation	of	the	provisions	of	current	accounting principles.

Deferred	tax	assets	are	reduced	by	valuation	allowances	if,	based	on	the	consideration	of	all	available	evidence,	it	is	more	likely	than	not	that	some	portion	of	the deferred	tax	asset	will	not	be	realized.	In	this	assessment,	significant	weight	is	given	to	evidence	that	can	be	objectively	verified.

We	assess	carryforwards	and	tax	credits	for	realization	as	a	reduction	of	future	taxable	income	by	using	a	"more	likely	than	not"	determination.

We	base	the	carrying	values	of	liabilities	and	assets	for	income	taxes	currently	payable	and	receivable	on	management's	interpretation	of	applicable	tax	laws	and incorporate	management's	assumptions	and	judgments	about	using	tax	planning	strategies	in	various	taxing	jurisdictions.	Using	different	estimates,	assumptions,	and judgments	in	accounting	for	income	taxes,	especially	those	that	deploy	tax	planning	strategies,	may	result	in	materially	different	carrying	values	of	income	tax	assets and	liabilities	and	changes	in	our	results	of	operations.

# Income	Tax	Accounting	Implications	of	the	Tax	Cuts	and	Jobs	Act

On	December	22,	2017,	the	Tax	Reform	Act	was	enacted	into	law	and	the	new	legislation	contained	several	key	tax	provisions	that	impacted	the	Company.		In December	2017,	the	SEC	staff	issued	Staff	Accounting	Bulletin	No.	118,	Income	Tax	Accounting	Implications	of	the	Tax	Cuts	and	Jobs	Act	("SAB	118"),	which allowed	registrants	to	record	provisional	amounts	during	a	measurement	period	not	to	extend	beyond	one	year	of	the	enactment	date.	Since	the	Tax	Reform	Act	was passed	late	in	the	fourth	quarter	of	2017	and	ongoing	guidance	and	accounting	interpretation	was	expected,	certain	items	were	considered	provisional	in	the	Company's financial	statements	for	2017	due	to	the	forthcoming	guidance	and	ongoing	analysis	of	year-end	data	and	tax	positions.	In	the	fourth	quarter	of	2018,	the	Company completed	its	analysis	in	accordance	with	SAB	118.		See	Note	11	"Income	Taxes"	of	the	Notes	to	Consolidated	Financial	Statements	in	Part	II,	Item	8	of	this	report	for additional	information	and	a	detailed	description	of	the	impact	of	completing	the	accounting	for	2017.

# NEW	ACCOUNTING	PRONOUNCEMENTS

Note	2	"Summary	of	Significant	Accounting	Principles	and	Practices"	of	the	Notes	to	Consolidated	Financial	Statements	contains	a	summary	of	our	significant accounting	policies,	 including	a	discussion	of	recently	 issued	accounting	pronouncements	and	 their	 impact	or	future	potential	 impact	on	our	financial	results,	 if determinable.

We	are	exposed	to	potential	fluctuations	in	earnings,	cash	flows,	and	the	fair	values	of	certain	of	our	assets	and	liabilities	due	to	changes	in	interest	rates	and	foreign exchange	rates.	To	manage	the	risk	from	these	exposures,	we	enter	into	a	variety	of	derivative	instruments.	We	do	not	enter	into	derivatives	or	financial	instruments	for trading	or	speculative	purposes.

The	following	discussion	describes	our	specific	exposures	and	the	strategies	we	use	to	manage	these	risks.	Refer	to	Note	2	"Summary	of	Significant	Accounting Principles	and	Practices"	of	the	Notes	to	Consolidated	Financial	Statements	in	Part	II,	Item	8	of	this	report	for	a	discussion	of	our	accounting	policies	for	financial instruments	and	derivatives.

# Foreign	Exchange	Risk

We	are	subject	to	foreign	exchange	rate	risk.	Our	primary	exposures	include	exchange	rates	between	the	U.S.	dollar	and	the	euro,	the	British	pound,	the	Canadian dollar,	the	Australian	dollar,	the	Indian	rupee,	and	the	Japanese	yen.	We	use	over-the-counter	options	and	forward	contracts	to	reduce	the	impact	of	foreign	currency	risk to	our	financial	statements.

Additionally,	some	of	our	non-U.S.	brokerage	subsidiaries	receive	revenues	in	currencies	that	differ	from	their	functional	currencies.	Our	U.K.	subsidiaries	earn	a portion	of	their	revenue	in	U.S.	dollars,	euros,	and	Japanese	yen,	but	most	of	their	expenses	are	incurred	in	British	pounds.	At	December	31,	2018,	we	have	hedged approximately	45%	of	our	U.K.	subsidiaries'	expected	exposures	to	the	U.S.	dollar,	euro,	and	Japanese	yen	transactions	for	the	years	ending	December	31,	2019,	2020, and	2021	respectively.	We	generally	do	not	hedge	exposures	beyond	three	years.

We	also	use	forward	contracts	to	economically	hedge	foreign	exchange	risk	associated	with	monetary	balance	sheet	exposures,	such	as	inter-company	notes	and short-term	assets	and	liabilities	that	are	denominated	in	a	non-functional	currency	and	are	subject	to	remeasurement.

The	potential	loss	in	future	earnings	from	foreign	exchange	derivative	instruments	resulting	from	a	hypothetical	10%	adverse	change	in	year-end	exchange	rates would	be	$21	million	and	$5	million	at	December	31,	2019	and	2020,	respectively.

Effective	July	1,	2018,	Argentina	was	designated	as	a	highly	inflationary	economy	and	therefore	the	functional	currency	for	our	Argentina	subsidiaries	became	the U.S.	dollar.	As	a	result,	the	impact	of	Argentine	peso	currency	fluctuations	in	these	subsidiaries	is	reported	within	the	Consolidated	Statements	of	Income	prospectively. We	are	undergoing	steps	to	limit	this	exposure	and	the	impact	to	2018	was	insignificant.	Revenue	from	our	Argentine	operations	was	less	than	1%	of	our	consolidated revenue	for	the	twelve	months	ended	December	31,	2018	and	2017.

# Interest	Rate	Risk

Our	fiduciary	investment	income	is	affected	by	changes	in	international	and	domestic	short-term	interest	rates.	We	monitor	our	net	exposure	to	short-term	interest rates,	and	as	appropriate,	hedge	our	exposure	with	various	derivative	financial	instruments.	This	activity	primarily	relates	to	brokerage	funds	held	on	behalf	of	clients	in the	North	America,	continental	Europe,	and	the	Asia	Pacific	region.	A	hypothetical,	instantaneous	parallel	decrease	in	the	year-end	yield	curve	of	100	basis	points	would cause	a	decrease,	net	of	derivative	positions,	of	$42	million	to	each	of	2019	and	2020	pretax	income.	A	corresponding	increase	in	the	year-end	yield	curve	of	100	basis points	would	cause	an	increase,	net	of	derivative	positions,	of	$42	million	to	each	of	2019	and	2020	pre-tax	income.

We	have	long-term	debt	outstanding	with	a	fair	market	value	of	$6.2	billion	at	both	December	31,	2018	and	2017.	This	fair	value	was	greater	than	the	carrying	value by	$166	million	at	December	31,	2018,	and	$600	million	greater	than	the	carrying	value	at	December	31,	2017.	A	hypothetical	1%	increase	or	decrease	in	interest	rates would	change	the	fair	value	by	a	decrease	of	7%	or	an	increase	of	8%,	respectively,	at	December	31,	2018.

We	have	selected	hypothetical	changes	in	foreign	currency	exchange	rates,	interest	rates,	and	equity	market	prices	to	illustrate	the	possible	impact	of	these	changes; we	are	not	predicting	market	events.

# Report	of	Independent	Registered	Public	Accounting	Firm

# Board	of	Directors	and	Shareholders

# Opinion	on	the	Financial	Statements

We	have	audited	the	accompanying	consolidated	statement	of	financial	position	of	Aon	plc	(the	Company)	as	of	December	31,	2018	and	2017,	and	the	related consolidated	statements	of	income,	comprehensive	income,	shareholders'	equity	and	cash	flows	for	each	of	the	three	years	in	the	period	ended	December	31,	2018,	and the	related	notes	(collectively	referred	to	as	the	"financial	statements").	In	our	opinion,	the	financial	statements	present	fairly,	in	all	material	respects,	the	consolidated financial	position	of	the	Company	at	December	31,	2018	and	2017,	and	the	consolidated	results	of	its	operations	and	its	cash	flows	for	each	of	the	three	years	in	the period	ended	December	31,	2018,	in	conformity	with	U.S.	generally	accepted	accounting	principles.

We	also	have	audited,	in	accordance	with	the	standards	of	the	Public	Company	Accounting	Oversight	Board	(United	States)	(PCAOB),	the	Company's	internal control	over	financial	reporting	as	of	December	31,	2018,	based	on	criteria	established	in	Internal	Control-Integrated	Framework	issued	by	the	Committee	of	Sponsoring Organizations	of	the	Treadway	Commission	(2013	Framework),	and	our	report	dated	February	19,	2019,	expressed	an	unqualified	opinion	thereon.

# Adoption	of	New	Accounting	Standards

As	discussed	in	Note	2	to	the	financial	statements,	the	Company	changed	its	method	of	accounting	for	revenue	in	2018.

# Basis	for	Opinion

These	financial	statements	are	the	responsibility	of	the	Company's	management.	Our	responsibility	is	to	express	an	opinion	on	the	Company's	financial	statements based	on	our	audits.	We	are	a	public	accounting	firm	registered	with	the	PCAOB	and	are	required	to	be	independent	with	respect	to	the	Company	in	accordance	with	the U.S.	federal	securities	laws	and	the	applicable	rules	and	regulations	of	the	Securities	and	Exchange	Commission	and	the	PCAOB.

We	conducted	our	audits	in	accordance	with	the	standards	of	the	PCAOB.	Those	standards	require	that	we	plan	and	perform	the	audit	to	obtain	reasonable assurance	about	whether	the	financial	statements	are	free	of	material	misstatement,	whether	due	to	error	or	fraud.	Our	audits	included	performing	procedures	to	assess the	risks	of	material	misstatement	of	the	financial	statements,	whether	due	to	error	or	fraud,	and	performing	procedures	that	respond	to	those	risks.	Such	procedures included	examining,	on	a	test	basis,	evidence	regarding	the	amounts	and	disclosures	in	the	financial	statements.	Our	audits	also	included	evaluating	the	accounting principles	used	and	significant	estimates	made	by	management,	as	well	as	evaluating	the	overall	presentation	of	the	financial	statements.	We	believe	that	our	audits provide	a	reasonable	basis	for	our	opinion.

We	have	served	as	the	Company's	auditor	since	1986.

Chicago,	Illinois

# Consolidated	Statements	of	Income

| (millions,	except	per	share	data) | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Revenue |  |  |  |
| Total\trevenue | $10,770 | $9,998 | $9,409 |
| Expenses |  |  |  |
| Compensation\tand\tbenefits | 6,103 | 6,003 | 5,514 |
| Information\ttechnology | 484 | 419 | 386 |
| Premises | 370 | 348 | 343 |
| Depreciation\tof\tfixed\tassets | 176 | 187 | 162 |
| Amortization\tand\timpairment\tof\tintangible\tassets | 593 | 704 | 157 |
| Other\tgeneral\texpenses | 1,500 | 1,272 | 1,036 |
| Total\toperating\texpenses | 9,226 | 8,933 | 7,598 |
| Operating\tincome | 1,544 | 1,065 | 1,811 |
| Interest\tincome | 5 | 27 | 9 |
| Interest\texpense | (278) | (282) | (282) |
| Other\tincome\t(expense) | (25) | (125) | (137) |
| Income\tfrom\tcontinuing\toperations\tbefore\tincome\ttaxes | 1,246 | 685 | 1,401 |
| Income\ttaxes | 146 | 250 | 148 |
| Net\tincome\tfrom\tcontinuing\toperations | 1,100 | 435 | 1,253 |
| Net\tincome\tfrom\tdiscontinued\toperations | 74 | 828 | 177 |
| Net\tincome | 1,174 | 1,263 | 1,430 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | 40 | 37 | 34 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $1,134 | $1,226 | $1,396 |
| Basic\tnet\tincome\tper\tshare\tattributable\tto\tAon\tshareholders |  |  |  |
| Continuing\toperations | $4.32 | $1.54 | $4.55 |
| Discontinued\toperations | 0.30 | 3.20 | 0.66 |
| Net\tincome | $4.62 | $4.74 | $5.21 |
| Diluted\tnet\tincome\tper\tshare\tattributable\tto\tAon\tshareholders |  |  |  |
| Continuing\toperations |  |  |  |
|  | $4.29 | $1.53 | $4.51 |
| Discontinued\toperations | 0.30 | 3.17 | 0.65 |
| Net\tincome | $4.59 | $4.70 | $5.16 |
| Weighted\taverage\tordinary\tshares\toutstanding\t-\tbasic | 245.2 | 258.5 | 268.1 |
| Weighted\taverage\tordinary\tshares\toutstanding\t-\tdiluted | 247.0 | 260.7 | 270.3 |

See	accompanying	Notes	to	Consolidated	Financial	Statements.

# Consolidated	Statements	of	Comprehensive	Income

| (millions) | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Net\tincome | $1,174 | $1,263 | $1,430 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | 40 | 37 | 34 |
| Net\tincome\tattributable\tto\tAon\tshareholders | 1,134 | 1,226 | 1,396 |
| Other\tcomprehensive\tincome\t(loss),\tnet\tof\ttax: |  |  |  |
| Change\tin\tfair\tvalue\tof\tfinancial\tinstruments | 11 | 12 | (12) |
| Foreign\tcurrency\ttranslation\tadjustments | (444) | 390 | (495) |
| Postretirement\tbenefit\tobligation | 17 | 19 | 16 |
| Total\tother\tcomprehensive\tincome\t(loss) | (416) | 421 | (491) |
| Less:\tOther\tcomprehensive\tincome\t(loss)\tattributable\tto\tnoncontrolling\tinterests | (4) | 5 | (2) |
| Total\tother\tcomprehensive\tincome\t(loss)\tattributable\tto\tAon\tshareholders | (412) | 416 | (489) |
| Comprehensive\tincome\tattributable\tto\tAon\tshareholders | $722 | $1,642 | $907 |

# Consolidated	Statements	of	Financial	Position

| (millions,	except	nominal	value) | 2018 | 2017 |
| :--- | :--- | :--- |
| Assets |  |  |
| Current\tassets |  |  |
| Cash\tand\tcash\tequivalents | $656 | $756 |
| Short-term\tinvestments | 172 | 529 |
| Receivables,\tnet | 2,760 | 2,478 |
| Fiduciary\tassets | 10,166 | 9,625 |
| Other\tcurrent\tassets | 618 | 289 |
| Total\tcurrent\tassets | 14,372 | 13,677 |
| Goodwill | 8,171 | 8,358 |
| Intangible\tassets,\tnet | 1,149 | 1,733 |
| Fixed\tassets,\tnet | 588 | 564 |
| Deferred\ttax\tassets | 561 | 389 |
| Prepaid\tpension | 1,133 | 1,060 |
| Other\tnon-current\tassets | 448 | 307 |
| Total\tassets | $26,422 | $26,088 |
| Liabilities\tand\tequity |  |  |
| Liabilities |  |  |
| Current\tliabilities |  |  |
| Accounts\tpayable\tand\taccrued\tliabilities | $1,943 | $1,961 |
| Short-term\tdebt\tand\tcurrent\tportion\tof\tlong-term\tdebt | 251 | 299 |
| Fiduciary\tliabilities | 10,166 | 9,625 |
| Other\tcurrent\tliabilities | 936 | 870 |
| Total\tcurrent\tliabilities | 13,296 | 12,755 |
| Long-term\tdebt | 5,993 | 5,667 |
| Deferred\ttax\tliabilities | 181 | 127 |
| Pension,\tother\tpostretirement,\tand\tpostemployment\tliabilities | 1,636 | 1,789 |
| Other\tnon-current\tliabilities | 1,097 | 1,102 |
| Total\tliabilities | 22,203 | 21,440 |
| Equity |  |  |
| Ordinary\tshares\t-\t$0.01\tnominal\tvalue\nAuthorized:\t750\tshares\t(issued:\t2018\t-\t240.1;\t2017\t-\t247.6) | 2 | 2 |
| Additional\tpaid-in\tcapital | 5,965 | 5,775 |
| Retained\tearnings | 2,093 | 2,302 |
| Accumulated\tother\tcomprehensive\tloss | (3,909) | (3,496) |
| Total\tAon\tshareholders'\tequity | 4,151 | 4,583 |
| Noncontrolling\tinterests | 68 | 65 |
| Total\tequity | 4,219 | 4,648 |
| Total\tliabilities\tand\tequity | $26,422 | $26,088 |

# Consolidated	Statements	of	Shareholders'	Equity

| (millions) | Shares | Ordinary	Shares	and<br>Additional	Paid-in<br>Capital | Retained<br>Earnings | Accumulated	Other<br>Comprehensive	Loss,	Net	of<br>Tax | Non-controlling<br>Interests | Total |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| Balance\tat\tJanuary\t1,\t2016 | 269.8 | $5,412 | $4,013 | $(3,423) | $57 | $6,059 |
| Net\tincome | — | — | 1,396 | — | 34 | 1,430 |
| Shares\tissued\t—\temployee\tstock\tcompensation\tplans | 4.3 | (125) | — | — | — | (125) |
| Shares\tpurchased | (12.1) | — | (1,257) | — | — | (1,257) |
| Tax\tbenefit\t—\temployee\tbenefit\tplans | — | (4) | — | — | — | (4) |
| Share-based\tcompensation\texpense | — | 331 | — | — | — | 331 |
| Dividends\tto\tshareholders\t($1.29\tper\tshare) | — | — | (345) | — | — | (345) |
| Net\tchange\tin\tfair\tvalue\tof\tfinancial\tinstruments | — | — | — | (12) | — | (12) |
| Net\tforeign\tcurrency\ttranslation\tadjustments | — | — | — | (493) | (2) | (495) |
| Net\tpostretirement\tbenefit\tobligation | — | — | — | 16 | — | 16 |
| Net\tpurchases\tof\tshares\tfrom\tnoncontrolling\tinterests | — | (34) | — | — | (4) | (38) |
| Dividends\tpaid\tto\tnoncontrolling\tinterests\ton\tsubsidiary\ncommon\tstock | — | — | — | — | (28) | (28) |
| Balance\tat\tDecember\t31,\t2016 | 262.0 | 5,580 | 3,807 | (3,912) | 57 | 5,532 |
| Adoption\tof\tnew\taccounting\tguidance | — | — | 49 | — | — | 49 |
| Balance\tat\tJanuary\t1,\t2017 | 262.0 | 5,580 | 3,856 | (3,912) | 57 | 5,581 |
| Net\tincome | — | — | 1,226 | — | 37 | 1,263 |
| Shares\tissued\t—\temployee\tstock\tcompensation\tplans | 3.6 | (120) | (1) | — | — | (121) |
| Shares\tpurchased | (18.0) | — | (2,415) | — | — | (2,415) |
| Share-based\tcompensation\texpense | — | 321 | — | — | — | 321 |
| Dividends\tto\tshareholders\t($1.41\tper\tshare) | — | — | (364) | — | — | (364) |
| Net\tchange\tin\tfair\tvalue\tof\tfinancial\tinstruments | — | — | — | 12 | — | 12 |
| Net\tforeign\tcurrency\ttranslation\tadjustments | — | — | — | 385 | 5 | 390 |
| Net\tpostretirement\tbenefit\tobligation | — | — | — | 19 | — | 19 |
| Net\tpurchases\tof\tshares\tfrom\tnoncontrolling\tinterests | — | (4) | — | — | (7) | (11) |
| Dividends\tpaid\tto\tnoncontrolling\tinterests\ton\tsubsidiary\ncommon\tstock | — | — | — | — | (27) | (27) |
| Balance\tat\tDecember\t31,\t2017 | 247.6 | 5,777 | 2,302 | (3,496) | 65 | 4,648 |
| Adoption\tof\tnew\taccounting\tguidance | — | — | 493 | (1) | — | 492 |
| Balance\tat\tJanuary\t1,\t2018 | 247.6 | 5,777 | 2,795 | (3,497) | 65 | 5,140 |
| Net\tincome | — | — | 1,134 | — | 40 | 1,174 |
| Shares\tissued\t—\temployee\tstock\tcompensation\tplans | 2.5 | (148) | — | — | — | (148) |
| Shares\tpurchased | (10.0) | — | (1,454) | — | — | (1,454) |
| Share-based\tcompensation\texpense | — | 338 | — | — | — | 338 |
| Dividends\tto\tshareholders\t($1.56\tper\tshare) | — | — | (382) | — | — | (382) |
| Net\tchange\tin\tfair\tvalue\tof\tfinancial\tinstruments | — | — | — | 11 | — | 11 |
| Net\tforeign\tcurrency\ttranslation\tadjustments | — | — | — | (440) | (4) | (444) |
| Net\tpostretirement\tbenefit\tobligation | — | — | — | 17 | — | 17 |
| Net\tpurchases\tof\tshares\tfrom\tnoncontrolling\tinterests | — | — | — | — | (1) | (1) |
| Dividends\tpaid\tto\tnoncontrolling\tinterests\ton\tsubsidiary\ncommon\tstock | — |  | — | — | (32) | (32) |
| Balance\tat\tDecember\t31,\t2018 | 240.1 | $5,967 | $2,093 | $(3,909) | $68 | $4,219 |

# Consolidated	Statements	of	Cash	Flows

| (millions) | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Cash\tflows\tfrom\toperating\tactivities |  |  |  |
| Net\tincome | $1,174 | $1,263 | $1,430 |
| Less:\tIncome\tfrom\tdiscontinued\toperations,\tnet\tof\tincome\ttaxes | 74 | 828 | 177 |
| Adjustments\tto\treconcile\tnet\tincome\tto\tcash\tprovided\tby\toperating\tactivities: |  |  |  |
| Loss\t(gain)\tfrom\tsales\tof\tbusinesses\tand\tinvestments,\tnet | 6 | 16 | (39) |
| Depreciation\tof\tfixed\tassets | 176 | 187 | 162 |
| Amortization\tand\timpairment\tof\tintangible\tassets | 593 | 704 | 157 |
| Share-based\tcompensation\texpense | 338 | 319 | 306 |
| Deferred\tincome\ttaxes | (225) | (18) | (24) |
| Change\tin\tassets\tand\tliabilities: |  |  |  |
| Fiduciary\treceivables | (679) | 171 | 595 |
| Short-term\tinvestments\t—\tfunds\theld\ton\tbehalf\tof\tclients | (320) | (135) | (540) |
| Fiduciary\tliabilities | 999 | (36) | (55) |
| Receivables,\tnet | (127) | (254) | (105) |
| Accounts\tpayable\tand\taccrued\tliabilities | 25 | 96 | 53 |
| Restructuring\treserves | 23 | 172 | — |
| Current\tincome\ttaxes | 34 | (914) | (42) |
| Pension,\tother\tpostretirement\tand\tother\tpostemployment\tliabilities | (259) | (66) | 42 |
| Other\tassets\tand\tliabilities | 2 | (8) | 66 |
| Cash\tprovided\tby\toperating\tactivities\t-\tcontinuing\toperations | 1,686 | 669 | 1,829 |
| Cash\tprovided\tby\toperating\tactivities\t-\tdiscontinued\toperations | — | 65 | 497 |
| Cash\tprovided\tby\toperating\tactivities | 1,686 | 734 | 2,326 |
| Cash\tflows\tfrom\tinvesting\tactivities |  |  |  |
| Proceeds\tfrom\tinvestments | 71 | 68 | 43 |
| Payments\tfor\tinvestments | (80) | (64) | (64) |
| Net\tsales\t(purchases)\tof\tshort-term\tinvestments\t—\tnon-fiduciary | 348 | (232) | 61 |
| Acquisition\tof\tbusinesses,\tnet\tof\tcash\tacquired | (58) | (1,029) | (879) |
| Sale\tof\tbusinesses,\tnet\tof\tcash\tsold | (10) | 4,246 | 107 |
| Capital\texpenditures | (240) | (183) | (156) |
| Cash\tprovided\tby\t(used\tfor)\tinvesting\tactivities\t-\tcontinuing\toperations | 31 | 2,806 | (888) |
| Cash\tused\tfor\tinvesting\tactivities\t-\tdiscontinued\toperations | — | (19) | (66) |
| Cash\tprovided\tby\t(used\tfor)\tinvesting\tactivities | 31 | 2,787 | (954) |
| Cash\tflows\tfrom\tfinancing\tactivities |  |  |  |
| Share\trepurchase | (1,470) | (2,399) | (1,257) |
| Issuance\tof\tshares\tfor\temployee\tbenefit\tplans | (149) | (121) | (129) |
| Issuance\tof\tdebt | 5,754 | 1,654 | 3,467 |
| Repayment\tof\tdebt | (5,417) | (1,999) | (2,945) |
| Cash\tdividends\tto\tshareholders | (382) | (364) | (345) |
| Noncontrolling\tinterests\tand\tother\tfinancing\tactivities | (35) | (36) | (77) |
| Cash\tused\tfor\tfinancing\tactivities\t-\tcontinuing\toperations | (1,699) | (3,265) | (1,286) |
| Cash\tused\tfor\tfinancing\tactivities\t-\tdiscontinued\toperations | — | — | — |
| Cash\tused\tfor\tfinancing\tactivities | (1,699) | (3,265) | (1,286) |
| Effect\tof\texchange\trates\ton\tcash\tand\tcash\tequivalents | (118) | 69 | (39) |
| Net\tincrease\t(decrease)\tin\tcash\tand\tcash\tequivalents | (100) | 325 | 47 |
| Cash\tand\tcash\tequivalents\tat\tbeginning\tof\tperiod | 756 | 431 | 384 |
| Cash\tand\tcash\tequivalents\tat\tend\tof\tperiod | $656 | $756 | $431 |
| Supplemental\tdisclosures: |  |  |  |
| Interest\tpaid | $266 | $272 | $272 |
| Income\ttaxes\tpaid,\tnet\tof\trefunds | $337 | $1,182 | $218 |

# 1.				Basis	of	Presentation

The	 accompanying	 Financial	 Statements	 have	 been	 prepared	 in	 accordance	 with	 U.S.	 generally	 accepted	 accounting	 principles	 ("U.S.	 GAAP").	 The	 Financial Statements	include	the	accounts	of	Aon	and	its	controlled	subsidiaries.	Intercompany	accounts	and	transactions	have	been	eliminated.	The	Financial	Statements	include, in	the	opinion	of	management,	all	adjustments	(consisting	of	normal	recurring	adjustments	and	reclassifications)	necessary	to	present	fairly	the	Company's	consolidated financial	position,	results	of	operations	and	cash	flows	for	all	periods	presented.

# Use	of	Estimates

The	preparation	of	the	accompanying	Financial	Statements	in	conformity	with	U.S.	GAAP	requires	management	to	make	estimates	and	assumptions	that	affect	the reported	amounts	of	assets	and	liabilities,	the	disclosures	of	contingent	assets	and	liabilities	at	the	date	of	the	financial	statements,	and	the	reported	amounts	of	reserves and	expenses.	These	estimates	and	assumptions	are	based	on	management's	best	estimates	and	judgments.	Management	evaluates	its	estimates	and	assumptions	on	an ongoing	basis	using	historical	experience	and	other	factors,	including	the	current	economic	environment.	Management	believes	its	estimates	to	be	reasonable	given	the current	facts	available.	Aon	adjusts	such	estimates	and	assumptions	when	facts	and	circumstances	dictate.	Illiquid	credit	markets,	volatile	equity	markets,	and	foreign currency	exchange	rate	movements	increase	the	uncertainty	inherent	in	such	estimates	and	assumptions.	As	future	events	and	their	effects	cannot	be	determined	with precision,	actual	results	could	differ	significantly	from	these	estimates.	Changes	in	estimates	resulting	from	continuing	changes	in	the	economic	environment	would,	if applicable,	be	reflected	in	the	Financial	Statements	in	future	periods.

# 2.				Summary	of	Significant	Accounting	Principles	and	Practices

# Principles	of	Consolidation

The	accompanying	consolidated	financial	statements	include	the	accounts	of	Aon	plc	and	those	entities	in	which	the	Company	has	a	controlling	financial	interest.	To determine	if	Aon	holds	a	controlling	financial	interest	in	an	entity,	the	Company	first	evaluates	if	it	is	required	to	apply	the	variable	interest	entity	(VIE)	model	to	the entity,	otherwise,	the	entity	is	evaluated	under	the	voting	interest	model.	Where	Aon	holds	rights	that	give	it	the	power	to	direct	the	activities	of	a	VIE	that	most significantly	impact	the	VIE's	economic	performance,	combined	with	a	variable	interest	that	gives	the	right	to	receive	potentially	significant	benefits	or	the	obligation	to absorb	potentially	significant	losses,	the	Company	has	a	controlling	financial	interest	in	that	VIE.	Aon	holds	a	controlling	financial	interest	in	entities	that	are	not	VIEs where	it,	directly	or	indirectly,	holds	more	than	50%	of	the	voting	rights	or	where	it	exercises	control	through	substantive	participating	rights	or	as	a	general	partner.

The	Company	generates	revenues	primarily	through	commissions,	compensation	from	insurance	and	reinsurance	companies	for	services	provided	to	them,	and	fees	from customers.	Commissions	and	fees	for	brokerage	services	vary	depending	upon	several	factors,	which	may	include	the	amount	of	premium,	the	type	of	insurance	or reinsurance	coverage	provided,	the	particular	services	provided	to	a	client,	insurer,	or	reinsurer,	and	the	capacity	in	which	the	Company	acts.	Compensation	from insurance	and	reinsurance	companies	includes:	(1)	fees	for	consulting	and	analytics	services	and	(2)	fees	and	commissions	for	administrative	and	other	services	provided to	or	on	behalf	of	insurers.	In	Aon's	capacity	as	an	insurance	and	reinsurance	broker,	the	service	promised	to	the	customer	is	placement	of	an	effective	insurance	or reinsurance	policy,	respectively.	At	the	completion	of	the	insurance	or	reinsurance	policy	placement	process	once	coverage	is	effective,	the	customer	has	obtained control	over	the	services	promised	by	the	Company.	Judgment	is	not	typically	required	when	assessing	whether	the	coverage	is	effective.	Fees	from	clients	for	advice and	consulting	services	are	dependent	on	the	extent	and	value	of	the	services	provided.	Payment	terms	for	the	Company's	principal	service	lines	are	discussed	below;	the Company	believes	these	terms	are	consistent	with	current	industry	practices.	Significant	financing	components	are	typically	not	present	in	Aon's	arrangements.

The	Company	has	elected	to	apply	practical	expedients	to	not	disclose	the	revenue	related	to	unsatisfied	performance	obligations	if	(1)	the	contract	has	an	original duration	of	1	year	or	less,	(2)	the	Company	has	recognized	revenue	for	the	amount	in	which	it	has	the	right	to	bill,	and	(3)	the	variable	consideration	is	allocated	entirely to	an	unsatisfied	performance	obligation	which	is	recognized	as	a	series	of	distinct	goods	or	services	that	form	a	single	performance	obligation.

# Disaggregation	of	Revenue

The	following	is	a	description	of	principal	service	lines	from	which	the	Company	generates	its	revenue:

# Share-Based	Compensation	Costs

Share-based	payments	to	employees,	including	grants	of	restricted	share	units	and	performance	share	awards,	are	measured	based	on	estimated	grant	date	fair	value.	The Company	recognizes	compensation	expense	over	the	requisite	service	period	for	awards	expected	to	ultimately	vest.	Forfeitures	are	estimated	on	the	date	of	grant	and revised	if	actual	or	expected	forfeiture	activity	differs	materially	from	original	estimates.

# Pension	and	Other	Postretirement	Benefits

The	Company	records	net	periodic	cost	relating	to	its	pension	and	other	postretirement	benefit	plans	based	on	calculations	that	include	various	actuarial	assumptions, including	discount	rates,	assumed	rates	of	return	on	plan	assets,	inflation	rates,	mortality	rates,	compensation	increases,	and	turnover	rates.	The	Company	reviews	its actuarial	assumptions	on	an	annual	basis	and	modifies	these	assumptions	based	on	current	rates	and	trends.	The	effects	of	gains,	losses,	and	prior	service	costs	and credits	are	amortized	over	future	service	periods	or	future	estimated	lives	if	the	plans	are	frozen.	The	funded	status	of	each	plan,	calculated	as	the	fair	value	of	plan	assets less	the	benefit	obligation,	is	reflected	in	the	Company's	Consolidated	Statements	of	Financial	Position	using	a	December	31	measurement	date.

# Net	Income	per	Share

Basic	net	income	per	share	is	computed	by	dividing	net	income	available	to	ordinary	shareholders	by	the	weighted-average	number	of	ordinary	shares	outstanding, including	participating	securities,	which	consist	of	unvested	share	awards	with	non-forfeitable	rights	to	dividends.	Diluted	net	income	per	share	is	computed	by	dividing net	income	available	to	ordinary	shareholders	by	the	weighted-average	number	of	ordinary	shares	outstanding,	which	have	been	adjusted	for	the	dilutive	effect	of potentially	issuable	ordinary	shares,	including	certain	contingently	issuable	shares.	The	diluted	earnings	per	share	calculation	reflects	the	more	dilutive	effect	of	either (1)	the	two-class	method	that	assumes	that	the	participating	securities	have	not	been	exercised,	or	(2)	the	treasury	stock	method.

Potentially	issuable	shares	are	not	included	in	the	computation	of	diluted	income	per	share	if	their	inclusion	would	be	antidilutive.

# Cash	and	Cash	Equivalents	and	Short-term	Investments

Cash	and	cash	equivalents	include	cash	balances	and	all	highly	liquid	investments	with	initial	maturities	of	three	months	or	less.	Short-term	investments	consist	of money	market	funds.	The	estimated	fair	value	of	Cash	and	cash	equivalents	and	Short-term	investments	approximates	their	carrying	values.

At	December	31,	2018,	Cash	and	cash	equivalents	and	Short-term	investments	totaled	$828	million	compared	to	$1,285	million	at	December	31,	2017.	Of	the	total balance,	$91	million	 and	$96	million	was	restricted	as	to	its	use	at	December	31,	2018	 and	2017,	respectively.	Included	within	 the	December	31,	2018	 and	2017 balances,	respectively,	were	£42.7	million	($53.9	million	at	December	31,	2018	exchanges	rates)	and	£42.7	million	($57.1	million	at	December	31,	2017	exchange	rates) of	operating	funds	required	to	be	held	by	the	Company	in	the	U.K.	by	the	FCA,	which	were	included	in	Short-term	investments.

# Fiduciary	Assets	and	Liabilities

In	its	capacity	as	an	insurance	agent	and	broker,	Aon	collects	premiums	from	insureds	and,	after	deducting	its	commission,	remits	the	premiums	to	the	respective insurers.	Aon	also	collects	claims	or	refunds	from	insurers	on	behalf	of	insureds.	Uncollected	premiums	from	insureds	and	uncollected	claims	or	refunds	from	insurers are	recorded	as	Fiduciary	assets	in	the	Company's	Consolidated	Statements	of	Financial	Position.	Unremitted	insurance	premiums	and	claims	are	held	in	a	fiduciary capacity	and	the	obligation	to	remit	these	funds	is	recorded	as	Fiduciary	liabilities	in	the	Company's	Consolidated	Statements	of	Financial	Position.

Aon	held	fiduciary	assets	for	premiums	collected	from	insureds	but	not	yet	remitted	to	insurance	companies	and	claims	collected	from	insurance	companies	but	not	yet remitted	to	insureds	of	$3.9	billion	and	$3.7	billion	at	December	31,	2018	and	2017,	respectively.	These	funds	and	a	corresponding	liability	are	included	in	Fiduciary assets	and	Fiduciary	liabilities,	respectively,	in	the	accompanying	Consolidated	Statements	of	Financial	Position.

# Allowance	for	Doubtful	Accounts

The	Company's	allowance	for	doubtful	accounts	with	respect	to	receivables	is	based	on	a	combination	of	factors,	including	evaluation	of	historical	write-offs,	aging	of balances,	and	other	qualitative	and	quantitative	analyses.	Receivables,	net	included	an	allowance	for	doubtful	accounts	of	$62	million	and	$59	million	at	December	31, 2018	and	2017,	respectively.

# Fixed	Assets

Fixed	assets	are	stated	at	cost,	less	accumulated	depreciation.	Included	in	this	category	is	internal	use	software,	which	is	software	that	is	acquired,	internally-developed or	modified	solely	to	meet	internal	needs,	with	no	plan	to	market	externally.	Costs	related	to	directly	obtaining,	developing,	or	upgrading	internal	use	software	are capitalized.	Depreciation	and	amortization	are	computed	using	the	straight-line	method	over	the	estimated	useful	lives	of	the	assets,	which	are	generally	as	follows:

# Goodwill	and	Intangible	Assets

Goodwill	represents	the	excess	of	acquisition	cost	over	the	fair	value	of	the	net	assets	in	the	acquisition	of	a	business.	Goodwill	is	allocated	to	various	reporting	units. Upon	disposition	of	a	business	entity,	goodwill	is	allocated	to	the	disposed	entity	based	on	the	fair	value	of	that	entity	compared	to	the	fair	value	of	the	reporting	unit	in which	it	was	included.	Goodwill	is	not	amortized,	but	instead	is	tested	for	impairment	at	least	annually.	The	goodwill	impairment	test	is	performed	at	the	reporting	unit level.	The	Company	may	initially	perform	a	qualitative	analysis	to	determine	if	it	is	more	likely	than	not	that	the	goodwill	balance	is	impaired.	If	a	qualitative assessment	is	not	performed	or	if	a	determination	is	made	that	it	is	not	more	likely	than	not	that	their	value	of	the	reporting	unit	exceeds	its	carrying	amount,	then	the Company	will	perform	a	two-step	quantitative	analysis.	First,	the	fair	value	of	each	reporting	unit	is	compared	to	its	carrying	value.	If	the	fair	value	of	the	reporting	unit is	less	than	its	carrying	value,	the	Company	performs	a	hypothetical	purchase	price	allocation	based	on	the	reporting	unit's	fair	value	to	determine	the	fair	value	of	the reporting	unit's	goodwill.	Any	resulting	difference	will	be	a	charge	to	Amortization	and	impairment	of	intangible	assets	in	the	Consolidated	Statements	of	Income	in	the period	in	which	the	determination	is	made.	Fair	value	is	determined	using	a	combination	of	present	value	techniques	and	market	prices	of	comparable	businesses.

We	classify	our	intangible	assets	acquired	as	either	tradenames,	customer-related	and	contract-based,	or	technology	and	other.	Amortization	basis	and	estimated	useful lives	by	intangible	asset	type	are	generally	as	follows:

# Derivatives

Derivative	instruments	are	recognized	in	the	Consolidated	Statements	of	Financial	Position	at	fair	value.	Where	the	Company	has	entered	into	master	netting	agreements with	counterparties,	the	derivative	positions	are	netted	by	counterparties	and	are	reported	accordingly	in	Other	assets	or	Other	liabilities.	Changes	in	the	fair	value	of derivative	instruments	are	recognized	in	earnings	each	period,	unless	the	derivative	is	designated	and	qualifies	as	a	cash	flow	or	net	investment	hedge.

The	Company	has	historically	designated	the	following	hedging	relationships	for	certain	transactions:	(1)	a	hedge	of	the	change	in	fair	value	of	a	recognized	asset	or liability	or	firm	commitment	("fair	value	hedge"),	(2)	a	hedge	of	the	variability	in	cash	flows	from	a	recognized	variable-rate	asset	or	liability	or	forecasted	transaction ("cash	flow	hedge"),	and	(3)	a	hedge	of	the	net	investment	in	a	foreign	operation	("net	investment	hedge").

In	order	for	a	derivative	to	qualify	for	hedge	accounting,	the	derivative	must	be	formally	designated	as	a	fair	value,	cash	flow,	or	a	net	investment	hedge	by	documenting the	relationship	between	the	derivative	and	the	hedged	item.	The	documentation	must

include	a	description	of	the	hedging	instrument,	the	hedged	item,	the	risk	being	hedged,	Aon's	risk	management	objective	and	strategy	for	undertaking	the	hedge,	the method	for	assessing	the	effectiveness	of	the	hedge,	and	the	method	for	measuring	hedge	ineffectiveness.	Additionally,	the	hedge	relationship	must	be	expected	to	be highly	effective	at	offsetting	changes	in	either	the	fair	value	or	cash	flows	of	the	hedged	item	at	both	the	inception	of	the	hedge	and	on	an	ongoing	basis.	Aon	assesses the	ongoing	effectiveness	of	its	hedges	and	measures	and	records	hedge	ineffectiveness,	if	any,	at	the	end	of	each	quarter	or	more	frequently	if	facts	and	circumstances require.

For	a	derivative	designated	as	a	fair	value	hedging	instrument,	the	gain	or	loss	is	recognized	in	earnings	in	the	period	of	change	together	with	the	offsetting	loss	or	gain on	the	hedged	item	attributable	to	the	risk	being	hedged.	The	effect	is	to	reflect	in	earnings	the	extent	to	which	the	hedge	is	not	effective	in	achieving	offsetting	changes in	fair	value.	For	a	cash	flow	hedge	that	qualifies	for	hedge	accounting,	the	effective	portion	of	the	change	in	fair	value	of	a	hedging	instrument	is	recognized	in	Other comprehensive	income	("OCI")	and	subsequently	reclassified	to	earnings	in	the	same	period	the	hedged	item	impacts	earnings.	The	ineffective	portion	of	the	change	in fair	value	is	recognized	immediately	in	earnings.	For	a	net	investment	hedge,	the	effective	portion	of	the	change	in	fair	value	of	the	hedging	instrument	is	recognized	in OCI	as	part	of	the	cumulative	translation	adjustment,	while	the	ineffective	portion	is	recognized	immediately	in	earnings.

Changes	in	the	fair	value	of	a	derivative	that	is	not	designated	as	part	of	a	hedging	relationship	(commonly	referred	to	as	an	"economic	hedge")	are	recorded	in	Other income	(expense)	in	the	Consolidated	Statements	of	Income.

The	Company	discontinues	hedge	accounting	prospectively	when	(1)	the	derivative	expires	or	is	sold,	terminated,	or	exercised,	(2)	the	qualifying	criteria	are	no	longer met,	or	(3)	management	removes	the	designation	of	the	hedging	relationship.

# Foreign	Currency

Certain	of	the	Company's	non-U.S.	operations	use	their	respective	local	currency	as	their	functional	currency.	These	operations	that	do	not	have	the	U.S.	dollar	as	their functional	currency	translate	their	financial	statements	at	the	current	rates	of	exchange	in	effect	at	the	balance	sheet	date	and	revenues	and	expenses	using	rates	that approximate	those	in	effect	during	the	period.	The	resulting	translation	adjustments	are	included	in	Net	foreign	currency	translation	adjustments	within	the	Consolidated Statements	of	Shareholders'	Equity.	Further,	for	all	entities,	gains	and	losses	from	the	remeasurement	of	monetary	assets	and	liabilities	that	are	denominated	in	a	non- functional	currency	of	that	entity	are	included	in	Other	income	(expense)	within	the	Consolidated	Statements	of	Income.

Deferred	income	taxes	are	recognized	for	the	effect	of	temporary	differences	between	financial	reporting	and	tax	basis	of	assets	and	liabilities	and	are	measured	using the	enacted	marginal	tax	rates	and	laws	that	are	currently	in	effect.	The	effect	on	deferred	tax	assets	and	liabilities	from	a	change	in	tax	rates	is	recognized	in	the	period when	the	rate	change	is	enacted.

Deferred	tax	assets	are	reduced	by	valuation	allowances	if,	based	on	the	consideration	of	all	available	evidence,	it	is	more	likely	than	not	that	some	portion	of	the deferred	tax	asset	will	not	be	realized.	Significant	weight	is	given	to	evidence	that	can	be	objectively	verified.	Deferred	tax	assets	are	realized	by	having	sufficient	future taxable	income	to	allow	the	related	tax	benefits	to	reduce	taxes	otherwise	payable.	The	sources	of	taxable	income	that	may	be	available	to	realize	the	benefit	of	deferred tax	assets	are	future	reversals	of	existing	taxable	temporary	differences,	future	taxable	income	exclusive	of	reversing	temporary	differences	and	carry-forwards,	taxable income	in	carry-back	years,	and	tax	planning	strategies	that	are	both	prudent	and	feasible.

The	Company	recognizes	the	effect	of	income	tax	positions	only	if	sustaining	those	positions	is	more	likely	than	not.	Tax	positions	that	meet	the	more	likely	than	not recognition	threshold	but	are	not	highly	certain	are	initially	and	subsequently	measured	based	on	the	largest	amount	of	benefit	that	is	greater	than	50%	likely	of	being realized	upon	settlement	with	the	taxing	authority.		Only	information	that	is	available	at	the	reporting	date	is	considered	in	the	Company's	recognition	and	measurement analysis,	and	events	or	changes	in	facts	and	circumstances	are	accounted	for	in	the	period	in	which	the	event	or	change	in	circumstance	occurs.

The	Company	records	penalties	and	interest	related	to	unrecognized	tax	benefits	in	Income	taxes	in	the	Company's	Consolidated	Statements	of	Income.

# Presentation	of	Net	Periodic	Pension	and	Postretirement	Benefit	Costs

In	March	2017,	the	Financial	Accounting	Standards	Board	("FASB")	issued	new	accounting	guidance	on	the	presentation	of	net	periodic	pension	cost	and	net	periodic postretirement	benefit	cost.	The	new	guidance	requires	that	an	employer	report	the	service	cost	component	in	the	same	line	item	or	items	as	other	compensation	costs arising	from	services	rendered	by	the	pertinent	employees

during	the	period.	It	also	requires	the	other	components	of	net	periodic	pension	cost	and	net	periodic	postretirement	benefit	cost	to	be	presented	in	the	income	statement separately	from	the	service	cost	component	and	outside	a	subtotal	of	income	from	operations,	if	one	is	presented.	Additionally,	only	the	service	cost	component	is eligible	for	capitalization,	when	applicable.	The	Company	has	applied	the	new	guidance	retrospectively	for	the	presentation	of	the	service	cost	component	and	the	other components	of	net	periodic	pension	cost	and	net	periodic	postretirement	benefit	cost	in	the	Consolidated	Statement	of	Income,	and	prospectively,	on	and	after	the effective	date,	for	the	capitalization	of	the	service	cost	component	of	net	periodic	pension	costs	and	net	periodic	postretirement	benefit	cost	in	assets.	The	new	guidance allows	a	practical	expedient	that	permits	an	employer	to	use	the	amounts	disclosed	in	its	pension	and	other	postretirement	benefit	plan	note	for	the	prior	comparative periods	as	the	estimation	basis	for	applying	the	retrospective	presentation	requirements.	The	Company	did	not	apply	the	practical	expedient	upon	adoption	of	this guidance.	The	new	guidance	was	effective	for	Aon	in	the	first	quarter	of	2018.	The	adoption	of	this	guidance	had	no	impact	on	the	net	income	of	the	Company.

Upon	adoption	of	the	guidance,	the	presentation	of	the	results	reflect	a	change	in	Operating	income	(loss)	offset	by	an	equal	and	offsetting	change	in	Other	income (expense)	for	each	period,	as	follows:

|  |  | 2017 |  |  | 2016 |  |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
|  | As\tReported | Adjustments | As\tAdjusted | As\tReported | Adjustments | As\tAdjusted |
| Operating\tincome\t(loss)\t(1) | $979 | $86 | $1,065 | $1,638 | $173 | $1,811 |
| Other\tincome\t(expense) | $(39) | $(86) | $(125) | $36 | $(173) | $(137) |

# (1) Reclassification	from	Operating	income	is	recorded	in	Compensation	and	benefits.

# Income	Tax	Consequences	of	Intercompany	Transactions

In	October	2016,	the	FASB	issued	new	accounting	guidance	on	the	income	tax	consequences	of	intra-entity	asset	transfers	other	than	inventory.	The	guidance	requires that	the	seller	and	buyer	recognize	the	consolidated	current	and	deferred	income	tax	consequences	of	a	transaction	in	the	period	the	transaction	occurs	rather	than deferring	to	a	future	period	and	recognizing	those	consequences	when	the	asset	has	been	sold	to	an	outside	party	or	otherwise	recovered	through	use	(i.e.	depreciated, amortized,	or	impaired).	The	Company	has	applied	the	new	guidance	on	a	modified	retrospective	basis	with	a	cumulative	effect	adjustment	to	retained	earnings	as	of	the beginning	of	the	period	of	adoption.	The	new	guidance	was	effective	for	Aon	in	the	first	quarter	of	2018.	Upon	the	adoption	of	this	guidance	on	January	1,	2018,	the Company	recognized	an	increase	to	Deferred	tax	assets	of	$23	million,	an	increase	to	Deferred	tax	liabilities	of	$12	million,	and	a	decrease	to	Other	non-current	assets of	$26	million	on	the	Consolidated	Statement	of	Financial	Position	through	a	cumulative	adjustment	of	$15	million	decrease	 to	Retained	earnings.	For	 the	twelve months	ended	December	31,	2018,	the	impact	of	adopting	this	guidance	on	the	Consolidated	Statement	of	Income	was	insignificant.

# Statement	of	Cash	Flows

In	August	2016,	the	FASB	issued	new	accounting	guidance	on	the	classification	of	certain	cash	receipts	and	cash	payments.	Under	the	new	guidance,	an	entity	no	longer has	discretion	to	choose	the	classification	for	a	number	of	transactions,	including	contingent	consideration	payments	made	after	a	business	combination,	proceeds	from the	settlement	of	insurance	claims,	proceeds	from	the	settlement	of	corporate-owned	life	insurance	policies,	and	distributions	received	from	equity	method	investees. The	new	standard	was	effective	for	the	Company	in	the	first	quarter	of	2018.	The	adoption	of	this	guidance	had	no	impact	on	the	Company's	Consolidated	Statements	of Cash	Flows.

# Financial	Assets	and	Liabilities

In	January	2016,	the	FASB	issued	new	accounting	guidance	on	recognition	and	measurement	of	financial	assets	and	financial	liabilities.	The	amendments	in	the	new guidance	make	targeted	improvements,	which	include	the	requirement	to	measure	equity	investments	with	readily	determinable	fair	values	at	fair	value	through	net income,	simplification	of	the	impairment	assessment	for	equity	investments	without	readily	determinable	fair	values,	adjustments	to	existing	and	additional	disclosure requirements,	and	additional	tax	considerations.	The	Company	applied	the	amendments	by	means	of	a	cumulative-effect	adjustment	to	the	balance	sheet	as	of	the beginning	of	the	fiscal	year	of	adoption,	with	the	exception	of	the	amendments	related	to	equity	securities	without	readily	determinable	fair	values,	including	disclosure requirements,	which	were	applied	prospectively.	Upon	the	adoption	of	this	guidance	on	January	1,	2018,	the	Company	recognized	an	increase	to	Accumulated	other comprehensive	loss	of	$1	million	on	the	Consolidated	Statement	of	Financial	Position	through	a	cumulative	adjustment	of	$1	million	increase	to	Retained	earnings.	For the	twelve	months	ended	December	31,	2018,	the	impact	of	adopting	this	guidance	on	the	Consolidated	Statement	of	Income	was	insignificant.

In	May	2014,	the	FASB	issued	a	new	accounting	standard	on	revenue	from	contracts	with	customers	(the	"Standard"	or	"ASC	606"),	which	supersedes	nearly	all existing	revenue	recognition	guidance	under	U.S.	GAAP	("ASC	605").	The	core	principal	of	the	Standard	is	that	an	entity	should	recognize	revenue	when	it	transfers promised	goods	or	services	 to	customers	 in	an	amount	 that	reflects	 the	consideration	 to	which	 the	entity	expects	 to	be	entitled	 in	exchange	for	 those	goods	or services.	The	Standard	also	requires	additional	disclosure	about	the	nature,	amount,	timing,	and	uncertainty	of	revenue	and	cash	flows	arising	from	customer	contracts, including	significant	judgments,	changes	in	judgments,	and	assets	recognized	from	costs	incurred	to	obtain	or	fulfill	a	contract.	Two	methods	of	transition	were permitted	upon	adoption:	full	retrospective	and	modified	retrospective.	The	Company	elected	to	apply	the	modified	retrospective	adoption	approach	to	all	contracts. Under	this	approach,	prior	periods	were	not	restated.	Rather,	revenues	and	other	disclosures	for	prior	periods	were	provided	in	the	notes	to	the	financial	statements	as previously	reported	under	ASC	605,	and	the	cumulative	effect	of	initially	applying	the	guidance	was	recognized	as	an	adjustment	to	Retained	earnings.

The	following	summarizes	the	significant	changes	to	the	Company	as	a	result	of	the	adoption	of	ASC	606	on	January	1,	2018.

•The	Company	previously	recognized	revenue	either	at	a	point	in	time	or	over	a	period	of	time	based	on	the	transfer	of	value	to	customers	or	as	the	remuneration became	determinable.	Under	ASC	606,	the	revenue	related	to	certain	brokerage	services	recognized	over	a	period	of	time	is	recognized	on	the	effective	date	of the	associated	policies	when	control	of	the	policy	transfers	to	the	customer.	As	a	result,	revenue	from	these	arrangements	are	typically	recognized	in	earlier periods	under	ASC	606	in	comparison	to	ASC	605,	changing	the	timing	and	amount	of	revenue	recognized	for	annual	and	interim	periods.	This	change	resulted in	a	significant	shift	in	timing	of	interim	revenue	for	the	Reinsurance	Solutions	revenue	line	and,	to	a	lesser	extent,	certain	other	brokerage	services.

•The	Standard	provides	guidance	on	accounting	for	certain	revenue-related	costs	including	when	to	capitalize	costs	associated	with	obtaining	and	fulfilling	a contract.	The	majority	of	these	costs	were	previously	expensed	as	incurred	under	ASC	605.	Assets	recognized	for	the	costs	to	obtain	a	contract,	which	includes certain	sales	commissions,	are	amortized	on	a	systematic	basis	that	is	consistent	with	the	transfer	of	the	services	to	which	the	asset	relates,	considering anticipated	renewals	when	applicable.	For	situations	where	the	renewal	period	is	one	year	or	less	and	renewal	costs	are	commensurate	with	the	initial	contract, the	Company	applied	a	practical	expedient	and	recognizes	the	costs	of	obtaining	a	contract	as	an	expense	when	incurred.	Assets	recognized	as	costs	to	fulfill	a contract,	which	includes	internal	costs	related	to	pre-placement	broking	activities,	as	well	as	other	costs,	are	amortized	on	a	systematic	basis	that	is	consistent with	the	transfer	of	the	services	to	which	the	asset	relates,	which	is	generally	less	than	one	year.

As	a	result	of	applying	the	modified	retrospective	method	to	adopt	ASC	606,	the	following	adjustments	were	made	to	the	Consolidated	Statement	of	Financial	Position as	of	January	1,	2018:

|  | December	31,<br>2017 |  | January	1,<br>2018 |
| :--- | :--- | :--- | :--- |
| (millions) | As\tReported | Adjustments | As\tAdjusted |
| Assets |  |  |  |
| Receivables,\tnet | $2,478 | $252 | $2,730 |
| Other\tcurrent\tassets | $289 | $298 | $587 |
| Deferred\ttax\tassets | $389 | $(128) | $261 |
| Other\tnon-current\tassets | $307 | $145 | $452 |
| Liabilities |  |  |  |
| Accounts\tpayable\tand\taccrued\tliabilities | $1,961 | $8 | $1,969 |
| Other\tcurrent\tliabilities | $870 | $13 | $883 |
| Deferred\ttax\tliabilities | $127 | $42 | $169 |
| Other\tnon-current\tliabilities | $1,102 | $(3) | $1,099 |
| Equity |  |  |  |
| Total\tequity | $4,648 | $507 | $5,155 |

The	following	tables	summarize	the	impacts	of	adopting	ASC	606	on	the	Company's	Consolidated	Statement	of	Income,	Financial	Position,	and	Cash	Flows	as	of	and for	the	twelve	months	ended	December	31,	2018.

# Consolidated	Statement	of	Income

| (millions) | As	Reported | Adjustments | 606 |
| :--- | :--- | :--- | :--- |
| Revenue |  |  |  |
| Total\trevenue | $10,770 | $(61) | $10,709 |
| Expenses |  |  |  |
| Compensation\tand\tbenefits | $6,103 | $51 | $6,154 |
| Other\tgeneral\texpenses | $1,500 | $(1) | $1,499 |
| Other\tincome\t(expense) | $(25) | $1 | $(24) |
| Income\ttaxes | $146 | $(34) | $112 |

Adoption	of	ASC	606	had	a	favorable	impact	of	$78	million	on	net	income	from	continuing	operations,	or	$0.32	per	share,	for	the	twelve	months	ended	December	31, 2018.

# Consolidated	Statement	of	Financial	Position

| (millions) | As	Reported | Adjustments | 606 |
| :--- | :--- | :--- | :--- |
| Assets |  |  |  |
| Receivables,\tnet | $2,760 | $(301) | $2,459 |
| Other\tcurrent\tassets | $618 | $(319) | $299 |
| Deferred\ttax\tassets | $561 | $137 | $698 |
| Other\tnon-current\tassets | $448 | $(155) | $293 |
| Liabilities |  |  |  |
| Other\tcurrent\tliabilities | $936 | $(43) | $893 |
| Deferred\ttax\tliabilities | $181 | $(28) | $153 |
| Other\tnon-current\tliabilities | $1,097 | $2 | $1,099 |
| Equity |  |  |  |
| Total\tequity | $4,219 | $(569) | $3,650 |

# Consolidated	Statement	of	Cash	Flows

| (millions) | As	Reported | Adjustments | 606 |
| :--- | :--- | :--- | :--- |
| Cash\tflows\tfrom\toperating\tactivities |  |  |  |
| Net\tincome | $1,174 | $(78) | $1,096 |
| Receivables,\tnet | $(127) | $49 | $(78) |
| Accounts\tpayable\tand\taccrued\tliabilities | $25 | $8 | $33 |
| Current\tincome\ttaxes | $34 | $(34) | $— |
| Other\tassets\tand\tliabilities | $2 | $55 | $57 |

The	adoption	of	ASC	606	had	no	impact	on	total	Cash	provided	by	operating	activities.

Refer	to	Note	3	"Revenue	from	Contracts	with	Customers"	for	further	information.

# Accounting	Standards	Issued	but	Not	Yet	Adopted

# Changes	to	the	Disclosure	Requirements	for	Defined	Benefit	Plans

In	August	2018,	 the	FASB	 issued	new	accounting	guidance	related	 to	 the	disclosure	requirements	for	employers	 that	sponsor	defined	benefit	pension	and	other postretirement	benefit	plans.	The	guidance	requires	sponsors	of	these	plans	to	provide	additional	disclosures,	including	weighted-average	interest	rates	used	in	the entity's	cash	balance	pension	plans	and	a	narrative	description	of	reasons	for	any	significant	gains	or	losses	impacting	the	benefit	obligation	for	the	period,	and eliminates	certain	previous	disclosure	requirements.	The	guidance	is	effective	for	Aon	in	the	first	quarter	of	2021	with	early	adoption	permitted	and	will	be	applied retrospectively.	The	Company	is	currently	evaluating	the	impact	that	the	guidance	will	have	on	the	Financial	Statements	and	the	period	of	adoption.

# Reclassification	of	Certain	Tax	Effects	from	Accumulated	Other	Comprehensive	Income

In	February	2018,	the	FASB	issued	new	accounting	guidance	related	to	reclassification	of	certain	tax	effects	from	accumulated	other	comprehensive	income.	The guidance	allows	a	reclassification	from	accumulated	comprehensive	income	to	retained	earnings	for	stranded	tax	effects	resulting	from	the	Tax	Reform	Act.	In	addition, the	entity	is	required	to	provide	certain	disclosures	regarding	stranded	tax	effects.	The	guidance	is	effective	for	Aon	in	the	first	quarter	of	2019	and	early	adoption	is permitted,	including	adoption	in	any	interim	period.	The	guidance	should	be	applied	either	in	the	period	of	adoption	or	retrospectively	to	each	period	(or	periods)	in which	the	effect	of	the	change	in	the	U.S.	federal	corporate	income	tax	rate	in	the	Tax	Reform	Act	is	recognized.	The	Company	does	not	anticipate	electing	to	reclassify stranded	tax	effects	in	accumulated	other	comprehensive	income	to	retained	earnings	and	will	adopt	the	disclosure	guidance	in	the	first	quarter	of	2019.	Refer	to	Note	11 "Income	Taxes"	for	further	discussion	of	the	Tax	Reform	Act.

# Targeted	Improvements	to	Accounting	for	Hedging	Activities

In	August	2017,	the	FASB	issued	new	accounting	guidance	on	targeted	improvements	to	accounting	for	hedging	activities.	The	new	guidance	amends	its	hedge accounting	model	to	enable	entities	to	better	portray	their	risk	management	activities	in	the	financial	statements.	The	guidance	eliminates	the	requirement	to	separately measure	and	report	hedge	ineffectiveness	and	requires	the	effect	of	a	hedging	instrument	to	be	presented	in	the	same	income	statement	line	as	the	hedged	item.	Further, in	December	2018,	the	FASB	issued	additional	guidance	which	added	to	the	list	of	U.S.	benchmark	interest	rates	that	are	eligible	to	be	hedged,	the	Overnight	Index Swap	("OIS")	rate	based	on	the	Secured	Overnight	Financing	Rate.	Thus,	entities	may	designate	the	OIS	rate	in	hedging	relationships	they	enter	into	on	or	after	the	date of	adoption	of	this	guidance.	An	entity	will	apply	the	new	guidance	on	a	modified	retrospective	basis	with	a	cumulative	effect	adjustment	to	accumulated	other comprehensive	income	with	a	corresponding	adjustment	to	retained	earnings	as	of	the	beginning	of	the	period	of	adoption.	Changes	to	income	statement	presentation and	financial	statement	disclosures	will	be	applied	prospectively.	The	new	guidance	is	effective	for	Aon	in	the	first	quarter	of	2019	and	early	adoption	is	permitted.	The Company	will	adopt	the	new	guidance	in	the	first	quarter	of	2019	and	does	not	expect	a	significant	impact	on	the	Financial	Statements.

# Simplifying	the	Test	for	Goodwill	Impairment

In	January	2017,	the	FASB	issued	new	accounting	guidance	on	simplifying	the	test	for	goodwill	impairment.	Currently	the	standard	requires	an	entity	to	perform	a	two- step	test	to	determine	the	amount,	if	any,	of	goodwill	impairment.	In	Step	1,	an	entity	compares	the	fair	value	of	a	reporting	unit	with	its	carrying	amount,	including goodwill.	If	the	carrying	amount	of	the	reporting	unit	exceeds	its	fair	value,	the	entity	performs	Step	2	and	compares	the	implied	fair	value	of	goodwill	with	the	carrying amount	of	that	goodwill	for	that	reporting	unit.	An	impairment	charge	equal	to	the	amount	by	which	the	carrying	amount	of	goodwill	for	the	reporting	unit	exceeds	the implied	fair	value	of	that	goodwill	is	recorded,	limited	to	the	amount	of	goodwill	allocated	to	that	reporting	unit.	The	new	guidance	removes	Step	2,	resulting	in	an	entity applying	a	line-step	quantitative	test	and	will	record	the	amount	of	goodwill	impairment	as	the	excess	of	a	reporting	unit's	carrying	amount	over	its	fair	value,	not	to exceed	the	total	amount	of	goodwill	allocated	to	the	reporting	unit.	The	new	guidance	does	not	amend	the	optional	qualitative	assessment	of	goodwill	impairment.	An entity	will	apply	the	new	guidance	on	a	prospective	basis.	The	new	guidance	is	effective	for	Aon	in	the	first	quarter	of	2020	and	early	adoption	is	permitted	beginning	in the	first	quarter	of	2019.	The	Company	is	currently	evaluating	the	period	of	adoption,	but	does	not	expect	a	significant	impact	on	the	Financial	Statements.

# Credit	Losses

In	June	2016,	the	FASB	issued	new	accounting	guidance	on	the	measurement	of	credit	losses	on	financial	instruments.	The	new	guidance	replaces	the	current	incurred loss	impairment	methodology	with	a	methodology	that	reflects	expected	credit	losses	and	requires	consideration	of	a	broader	range	of	reasonable	and	supportable information	to	inform	credit	loss	estimates.	An	entity	will	apply	the	new	guidance	through	a	cumulative-effect	adjustment	to	retained	earnings	as	of	the	beginning	of	the first	reporting	period	in	which	the	guidance	is	effective.	The	guidance	is	effective	for	Aon	in	the	first	quarter	of	2020	and	early	adoption	is	permitted	beginning	in	the first	quarter	of	2019.	The	Company	is	currently	evaluating	the	impact	that	the	standard	will	have	on	the	Financial	Statements	and	period	of	adoption.

# Leases

In	February	2016,	the	FASB	issued	a	new	accounting	standard	on	leases,	which	requires	lessees	to	recognize	assets	and	liabilities	for	most	leases.	Under	the	new standard,	 a	 lessee	 is	 required	 to	 recognize	 in	 the	 Consolidated	 Statement	 of	 Financial	 Position	 liabilities	 to	 make	 future	 lease	 payments	 and	 right-of-use	 assets representing	its	right	to	use	the	underlying	assets	for	the	lease	term.	The	recognition,	measurement,	timing,	and	presentation	of	expenses	and	cash	flows	arising	from	a lease	by	a	lessee	have	not	significantly	changed	from	current	U.S.	GAAP	standards.	The	new	standard	is	effective	for	the	Company	in	the	first	quarter	of	2019,	with early	adoption	permitted	and	must	be	applied	using	a	modified	retrospective	transition	approach.	In	July	2018,	the	FASB	amended	this	guidance	and	provided	an additional	transition	method	with	which	to	adopt	the	guidance.	Under	the	additional	transition	method,	entities	may	elect	to	recognize	a	cumulative-effect	adjustment	to the	opening	balance	of	retained	earnings	in	the	year	of	adoption.	Under	this	transition	method,	an	entity's	reporting	for	the	comparative	periods	prior	to	adoption presented	in	the	financial	statements	would	continue	to	be	in	accordance	with	current	lease	guidance	and	thus	not	restated.	The	Company	will	adopt	the	new	standard	as of	January	1,	2019	using	the	cumulative-effect	adjustment	transition	method	approved	by	the	FASB.	Additionally,	the	Company	will	provide	expanded	lease	disclosures required	under	the	new	standard	in	the	first	quarter	of	2019,	including	both	qualitative	and	quantitative	information.

The	modified	retrospective	approach	includes	several	optional	practical	expedients	that	entities	may	elect	to	apply	upon	transition.	The	Company	has	determined	it	will elect	the	package	of	practical	expedients	permitted	under	the	transition	guidance	within	the	new	standard,	which	allows	a	lessee	to	carryforward	their	population	of existing	leases,	the	classification	of	each	lease,	as	well	as	the	treatment	of	initial	direct	costs	as	of	the	period	of	adoption.	In	addition,	the	Company	will	elect	the practical	expedient	related	to	lease	and	non-lease	components,	as	an	accounting	policy	election	for	all	asset	classes,	which	allows	a	lessee	to	not	separate	non-lease	from lease	components	and	instead	account	for	consideration	paid	in	a	contract	as	a	single	lease	component.	Furthermore,	the	Company	has	made	a	policy	election	to	not recognize	right-of-use	assets	and	lease	liabilities	that	arise	from	leases	with	an	initial	term	of	twelve	months	or	less	on	the	Consolidated	Statements	of	Financial Position.	Lastly,	the	Company	has	determined	it	will	not	elect	the	practical	expedient	related	to	hindsight	in	determining	the	lease	term	and	in	assessing	impairment	of right-of-use	assets.

The	Company	will	implement	the	standard	as	of	January	1,	2019	and	has	executed	a	comprehensive	approach	to	identify	arrangements	that	may	contain	a	lease,	has performed	completeness	assessments	over	the	identified	lease	population,	and	has	implemented	system	solutions	and	processes	to	appropriately	account	for	the	lease right-of-use	assets	and	lease	liabilities	upon	transition	and	an	ongoing	basis.	Further,	control	activities	related	to	the	adoption	of	this	standard	as	well	as	ongoing transactional	processes	and	procedures	have	been	designed	and	begun	to	be	implemented	to	ensure	compliance	with	the	new	standard.

The	Company	expects	to	recognize	lease	liabilities	ranging	from	approximately	$1.3	billion	 to	$1.5	billion	and	corresponding	right-of-use	assets	ranging	from	$1.1 billion	to	$1.3	billion	on	the	Consolidated	Statements	of	Financial	Position	upon	the	adoption	of	this	standard.	The	Company	does	not	anticipate	that	the	new	standard will	have	a	significant	impact	on	the	Consolidated	Statements	of	Income	or	the	Consolidated	Statements	of	Cash	Flows.

# 3.	Revenue	from	Contracts	with	Customers

The	following	table	summarizes	revenue	from	contracts	with	customers	by	principal	service	line	(in	millions):

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Commercial\tRisk\tSolutions | $4,652 | $4,169 | $3,929 |
| Reinsurance\tSolutions | 1,563 | 1,429 | 1,361 |
| Retirement\tSolutions | 1,865 | 1,755 | 1,707 |
| Health\tSolutions | 1,596 | 1,515 | 1,370 |
| Data\t&amp;\tAnalytic\tServices | 1,105 | 1,140 | 1,050 |
| Elimination | (11) | (10) | (8) |
| Total\trevenue | $10,770 | $9,998 | $9,409 |

Consolidated	revenue	from	contracts	with	customers	by	geographic	area,	which	is	attributed	on	the	basis	of	where	the	services	are	performed,	is	as	follows	(in	millions):

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| United\tStates | $4,677 | $4,425 | $3,981 |
| Americas\tother\tthan\tUnited\tStates | 940 | 976 | 899 |
| United\tKingdom | 1,555 | 1,436 | 1,354 |
| Europe,\tMiddle\tEast,\t&amp;\tAfrica\tother\tthan\tUnited\tKingdom | 2,413 | 2,025 | 1,760 |
| Asia\tPacific | 1,185 | 1,136 | 1,415 |
| Total\trevenue | $10,770 | $9,998 | $9,409 |

# Contract	Costs

The	Company	recognizes	an	asset	for	costs	incurred	to	fulfill	a	contract	for	costs	that	are	specifically	identified	and	relate	to	a	contract	or	anticipated	contract,	generate	or enhance	resources	used	in	satisfying	the	Company's	performance	obligations,	and	are	expected	to	be	recovered.	Assets	recognized	as	costs	to	fulfill	a	contract,	which includes	internal	costs	related	to	pre-placement	broking	activities,	as	well	as	other	costs,	are	amortized	on	a	systematic	basis	that	is	consistent	with	the	transfer	of	control of	the	services	to	which	the	asset	relates.	The	amortization	is	primarily	included	in	Compensation	and	benefits	on	the	Consolidated	Statements	of	Income.

An	analysis	of	the	changes	in	the	net	carrying	amount	of	costs	to	fulfill	contracts	with	customers	is	as	follows	(in	millions):

(1) Upon	adoption	of	the	new	revenue	recognition	standard	on	January	1,	2018,	Aon	capitalized	$298	million	of	costs	to	fulfill	contracts	with	customers.

The	Company	capitalizes	incremental	costs	to	obtain	a	contract	with	a	customer	that	are	expected	to	be	recovered.	Assets	recognized	for	the	costs	to	obtain	a	contract, which	includes	certain	sales	commissions,	will	be	amortized	on	a	systematic	basis	that	is	consistent	with	the	transfer	of	control	of	the	services	to	which	the	asset	relates, considering	anticipated	renewals	when	applicable.	For	situations	where	the	renewal	period	is	one	year	or	less	and	renewal	costs	are	commensurate	with	the	initial contract,	the	Company	has	applied	a	practical	expedient	and	recognized	the	costs	of	obtaining	a	contract	as	an	expense	when	incurred.	The	amortization	is	primarily included	in	Compensation	and	benefits	on	the	Consolidated	Statements	of	Income.

An	analysis	of	the	changes	in	the	net	carrying	amount	of	costs	to	obtain	contracts	with	customers	is	as	follows	(in	millions):

(1) Upon	adoption	of	the	new	revenue	recognition	standard	on	January	1,	2018,	Aon	capitalized	$145	million	of	costs	to	obtain	contracts	with	customers.

Please	refer	to	Note	2	"Summary	of	Significant	Accounting	Principles	and	Practices"	for	further	information	regarding	the	Company's	revenue	recognition	policy.

# 4.				Other	Financial	Data

# Consolidated	Statements	of	Income	Information

Other	income	(expense)	consists	of	the	following	(in	millions):

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Foreign\tcurrency\tremeasurement | $25 | $(37) | $(2) |
| Disposal\tof\tbusiness | (6) | (16) | 39 |
| Pension\tand\tother\tpostretirement | 1 | (86) | (173) |
| Equity\tearnings | 4 | 12 | 13 |
| Financial\tinstruments | (49) | 2 | (14) |
| Total | $(25) | $(125) | $(137) |

# Consolidated	Statements	of	Financial	Position	Information

An	analysis	of	the	allowance	for	doubtful	accounts	is	as	follows	(in	millions):

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Balance\tat\tJanuary\t1 | $59 | $56 | $58 |
| Provision\tcharged\tto\tOther\tgeneral\texpenses | 24 | 18 | 10 |
| Accounts\twritten\toff,\tnet\tof\trecoveries | (25) | (18) | (15) |
| Foreign\tcurrency\ttranslation | 4 | 3 | 3 |
| Balance\tat\tDecember\t31 | $62 | $59 | $56 |

# Other	Current	Assets

The	components	of	Other	current	assets	are	as	follows	(in	millions):

| As	of	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| Costs\tto\tfulfill\tcontracts\twith\tcustomers\t(1) | $329 | $— |
| Taxes\treceivable | 113 | 114 |
| Prepaid\texpenses | 97 | 126 |
| Receivables\tfrom\tthe\tDivested\tBusiness\t(2) | 12 | 28 |
| Other | 67 | 21 |
| Total | $618 | $289 |

(2) Refer	to	Note	5	"Discontinued	Operations"	for	further	information.

# Fixed	Assets,	net

The	components	of	Fixed	assets,	net	are	as	follows	(in	millions):

| As	of	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| Software | $693 | $680 |
| Leasehold\timprovements | 334 | 349 |
| Computer\tequipment | 279 | 295 |
| Furniture,\tfixtures\tand\tequipment | 228 | 240 |
| Construction\tin\tprogress | 154 | 79 |
| Other | 45 | 90 |
| Fixed\tassets,\tgross | 1,733 | 1,733 |
| Less:\tAccumulated\tdepreciation | 1,145 | 1,169 |
| Fixed\tassets,\tnet | $588 | $564 |

Depreciation	expense,	which	includes	software	amortization,	was	$176	million,	$187	million,	and	$162	million	for	the	years	ended	December	31,	2018,	2017,	and	2016, respectively.

# Other	Non-Current	Assets

The	components	of	Other	non-current	assets	are	as	follows	(in	millions):

| As	of	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| Costs\tto\tobtain\tcontracts\twith\tcustomers\t(1) | $156 | $— |
| Investments | 54 | 57 |
| Taxes\treceivable | 100 | 84 |
| Other | 138 | 166 |
| Total | $448 | $307 |

# Other	Current	Liabilities

The	components	of	Other	current	liabilities	are	as	follows	(in	millions):

| As	of	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| Deferred\trevenue\t(1) | $251 | $311 |
| Taxes\tpayable\t(2) | 83 | 139 |
| Other | 602 | 420 |
| Total | $936 | $870 |

(1) During	the	twelve	months	ended	December	31,	2018,	$487	million	was	recognized	in	the	Consolidated	Statements	of	Income.

(2) Includes	$42	million	for	the	current	portion	of	the	Transition	Tax	as	of	December	31,	2017.	Refer	to	Note	11	"Income	Taxes"	for	further	information	on	the	Transition	Tax.

# Other	Non-Current	Liabilities

The	components	of	Other	non-current	liabilities	are	as	follows	(in	millions):

| As	of	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| Taxes\tpayable\t(1) | $585 | $529 |
| Leases | 169 | 153 |
| Compensation\tand\tbenefits | 56 | 67 |
| Deferred\trevenue | 65 | 49 |
| Other | 222 | 304 |
| Total | $1,097 | $1,102 |

(1) Includes	$240	million	and	$222	million	for	the	non-current	portion	of	the	Transition	Tax,	as	of	December	31,	2018	and	December	31,	2017,	respectively.	Refer	to	Note	11	"Income	Taxes"	for further	information	on	the	Transition	Tax.

# 5.	Discontinued	Operations

On	February	9,	2017,	the	Company	entered	into	a	Purchase	Agreement	with	Tempo	Acquisition,	LLC	(the	"Purchase	Agreement")	to	sell	the	Divested	Business	to	an entity	formed	and	controlled	by	affiliates	of	The	Blackstone	Group	L.P.	(the	"Buyer")	and	certain	designated	purchasers	that	are	direct	or	indirect	subsidiaries	of	the Buyer.

On	May	1,	2017,	the	Buyer	purchased	all	of	the	outstanding	equity	interests	of	the	Divested	Business,	plus	certain	related	assets	and	liabilities,	for	a	purchase	price	of $4.3	billion	in	cash	paid	at	closing,	subject	to	customary	adjustments	set	forth	in	the	Purchase	Agreement,	and	deferred	consideration	of	up	to	$500	million.	Cash proceeds	after	customary	adjustments	and	before	taxes	due	were	$4.2	billion.

Aon	and	the	Buyer	entered	into	certain	transaction	related	agreements	at	the	closing,	including	two	commercial	agreements,	a	transition	services	agreement,	certain intellectual	property	license	agreements,	sub-leases,	and	other	customary	agreements.	Aon	expects	to	continue	to	be	a	significant	client	of	the	Divested	Business	and	the Divested	Business	has	agreed	to	use	Aon	for	its	broking	and	other	services	for	a	specified	period	of	time.

The	financial	results	of	the	Divested	Business	for	the	years	ended	December	31,	2018,	2017,	and	2016	are	presented	as	Net	income	from	discontinued	operations	on	the Company's	Consolidated	Statements	of	Income.	The	following	table	presents	the	financial	results	of	the	Divested	Business	(in	millions):

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Revenue |  |  |  |
| Total\trevenue | $— | $698 | $2,218 |
| Expenses |  |  |  |
| Total\toperating\texpenses | 12 | 656 | 1,950 |
| Operating\tIncome\tfrom\tdiscontinued\toperations | (12) | 42 | 268 |
| Other\tincome | — | 10 | — |
| Income\tfrom\tdiscontinued\toperations\tbefore\tincome\ttaxes | (12) | 52 | 268 |
| Income\ttax\texpense\t(benefit) | (4) | 3 | 91 |
| Net\tincome\t(loss)\tfrom\tdiscontinued\toperations,\texcluding\tgain | (8) | 49 | 177 |
| Gain\ton\tsale\tof\tdiscontinued\toperations,\tnet\tof\ttax | 82 | 779 | — |
| Net\tincome\tfrom\tdiscontinued\toperations | $74 | $828 | $177 |

Upon	 triggering	held	for	sale	criteria	 in	February	2017,	Aon	ceased	depreciating	and	amortizing	all	 long-lived	assets	 included	 in	discontinued	operations.	Total operating	expenses	for	the	years	ended	December	31,	2017,	and	2016	include,	respectively,	$8	million	and	$70	million	of	depreciation	of	fixed	assets	and	$11	million and	$120	million	of	intangible	asset	amortization	for	the	time	prior	to	the	Company	triggering	held	for	sale	criteria.

The	 Company's	 Consolidated	 Statements	 of	 Cash	 Flows	 present	 the	 operating,	 investing,	 and	 financing	 cash	 flows	 of	 the	 Divested	 Business	 as	 discontinued operations.	Aon	uses	a	centralized	approach	to	cash	management	and	financing	of	its	operations.	Prior	to	the	closing	of	the	Transaction,	portions	of	the	Divested Business's	cash	were	transferred	to	Aon	daily,	and	Aon	would	fund	the	Divested	Business	as	needed.	There	were	 no	Cash	and	cash	equivalents	of	discontinued operations	at	December	31,	2017.	Total	proceeds	received	for	the	sale	of	the	Divested	Business	and	taxes	paid	as	a	result	of	the	sale	are	recognized	on	the	Consolidated Statements	 of	 Cash	 Flows	 in	 Cash	 provided	 by	 investing	 activities	 -	 continuing	 operations	 and	 Cash	 provided	 by	 operating	 activities	 -	 continuing	 operations, respectively.

In	2017,	Aon	initiated	a	global	restructuring	plan	(the	"Restructuring	Plan")	in	connection	with	the	sale	of	the	Divested	Business.	The	Restructuring	Plan	is	intended	to streamline	operations	across	the	organization	and	deliver	greater	efficiency,	insight,	and	connectivity.	The	Company	expects	these	restructuring	activities	and	related expenses	to	affect	continuing	operations	through	the	fourth	quarter	of	2019,	including	an	estimated	4,800	to	5,400	role	eliminations.	In	the	fourth	quarter	of	2018,	Aon expanded	the	Restructuring	Plan,	which	resulted	in	additional	expected	costs	of	approximately	$200	million,	consisting	of	$150	million	of	cash	investment	and	$50 million	of	non-cash	charges.

The	Restructuring	Plan	is	expected	to	result	in	cumulative	costs	of	approximately	$1,225	million	through	the	end	of	the	plan,	consisting	of	approximately	$450	million	in employee	termination	costs,	$130	million	in	technology	rationalization	costs,	$65	million	in	lease	consolidation	costs,	$50	million	in	non-cash	asset	impairments,	and $530	million	in	other	costs,	including	certain	separation	costs	associated	with	the	sale	of	the	Divested	Business.

From	the	inception	of	the	Restructuring	Plan	through	December	31,	2018,	the	Company	has	eliminated	4,366	positions	and	incurred	total	expenses	of	$982	million	for restructuring	and	related	separation	costs.	These	charges	are	included	in	Compensation	and	benefits,	Information	technology,	Premises,	Depreciation	of	fixed	assets,	and Other	general	expenses	in	the	accompanying	Consolidated	Statements	of	Income.

The	following	table	summarizes	restructuring	and	separation	costs	by	type	that	have	been	incurred	through	December	31,	2018	and	are	estimated	to	be	incurred	through the	end	of	the	Restructuring	Plan	(in	millions).	Estimated	costs	by	type	may	be	revised	in	future	periods	as	these	assumptions	are	updated:

|  | Year	Ended	December	31,<br>2018 | Inception	to	Date | Estimated	Remaining	Costs | Estimated	Total	Cost	(1) |
| :--- | :--- | :--- | :--- | :--- |
| Workforce\treduction | $115 | $414 | $36 | $450 |
| Technology\trationalization\t(2) | 47 | 80 | 50 | 130 |
| Lease\tconsolidation\t(2) | 28 | 36 | 29 | 65 |
| Asset\timpairments | 13 | 39 | 11 | 50 |
| Other\tcosts\tassociated\twith\trestructuring\tand\tseparation\t(2) |  |  |  |  |
| (3) | 282 | 413 | 117 | 530 |
| Total\trestructuring\tand\trelated\texpenses | $485 | 982 | $243 | $1,225 |

(3) Other	costs	associated	with	the	Restructuring	Plan	include	primarily	those	to	separate	the	Divested	Business,	as	well	as	moving	costs	and	consulting	and	legal	fees.	These	costs	are	generally      recognized	when	incurred.

The	changes	in	the	Company's	liabilities	for	the	Restructuring	Plan	as	of	December	31,	2018	are	as	follows	(in	millions):

# Acquisitions

The	 Company	 completed	eight	acquisitions	during	 the	year	ended	December	31,	2018	 and	seventeen	 acquisitions	 during	 the	 year	 ended	December	31,	2017.	 The following	table	includes	the	preliminary	fair	values	of	consideration	transferred,	assets	acquired,	and	liabilities	assumed	as	a	result	of	the	Company's	acquisitions	(in millions):

|  | For	the	year	ended	December	31,<br>2018 |
| :--- | :--- |
| Consideration\ttransferred |  |
| Cash | $55 |
| Deferred\tand\tcontingent\tconsideration | 18 |
| Aggregate\tconsideration\ttransferred | $73 |
| Assets\tacquired |  |
| Cash\tand\tcash\tequivalents | $1 |
| Receivables,\tnet | 4 |
| Goodwill | 38 |
| Intangible\tassets,\tnet | 34 |
| Other\tassets | 4 |
| Total\tassets\tacquired | 81 |
| Liabilities\tassumed |  |
| Current\tliabilities | 6 |
| Other\tliabilities | 2 |
| Total\tliabilities\tassumed | 8 |
| Net\tassets\tacquired | $73 |

Intangible	assets	are	primarily	customer-related	and	contract-based	assets.	Those	intangible	assets	acquired	as	part	of	a	business	acquisition	in	2018	had	a	weighted average	useful	economic	life	of	7	years.	Acquisition	related	costs	incurred	and	recognized	within	Other	general	expenses	for	the	year	ended	December	31,	2018	were	$2 million.	Total	revenue	for	these	acquisitions	included	in	the	Company's	Consolidated	Statement	of	Income	for	the	year	ended	December	31,	2018	was	approximately $17	million.

The	results	of	operations	of	these	acquisitions	are	included	in	the	Consolidated	Financial	Statements	as	of	the	respective	acquisition	dates.	The	results	of	operations	of	the Company	would	not	have	been	materially	different	if	these	acquisitions	had	been	reported	from	the	beginning	of	the	period	in	which	they	were	acquired.

# 2018	Acquisitions

On	December	31,	2018,	the	Company	completed	the	transaction	to	acquire	certain	assets	of	Bill	Beatty	Insurance	Agency,	Inc.	based	in	the	United	States.

On	November	15,	2018,	the	Company	completed	the	transaction	to	acquire	certain	business	and	assets	of	North	Harbour	Insurance	Services	(1985)	Limited,	a	New Zealand-based	firm.

On	 October	 25,	 2018, the	 Company	 completed the transaction to	 acquire	 100%	 capital	 of	 GEFASS	 S.R.L	 and	 GE.F.IT	 S.R.L.,	 Italy-based	 firms	 specialized in Bancassurance	schemes.

On	May	9,	2018,	the	Company	completed	the	transaction	to	acquire	certain	assets	of	601West,	a	division	of	Lee	&	Hayes,	P.L.L.C.	based	in	the	United	States.

On	April	24,	2018,	the	Company	completed	the	transaction	to	acquire	Inspiring	Benefits,	S.L.,	a	Spain-based	firm	specialized	in	employee	loyalty,	wellbeing,	and rewards	programs.

On	March	1,	2018,	the	Company	completed	the	transaction	to	acquire	the	business	and	assets	of	the	trade	credit	business	of	Niche	International	Business	Proprietary Limited,	a	trade	credit	brokerage	based	in	Johannesburg,	South	Africa.

On	March	1,	2018,	the	Company	completed	the	transaction	to	acquire	Affinity	Risk	Partners	(Brokers)	Pty.	Ltd.,	an	insurance	broker	in	Victoria,	Australia.

On	January	19,	2018,	the	Company	completed	the	transaction	to	acquire	substantially	all	of	the	assets	of	The	Burchfield	Group,	a	provider	in	pharmacy	benefit consulting,	auditing,	and	health	plan	compliance	services	based	in	the	United	States.

On	December	29,	2017,	the	Company	completed	the	transaction	to	acquire	the	Townsend	Group,	a	U.S.-based	provider	of	global	investment	management	and	advisory services	primarily	focused	on	real	estate.

On	December	29,	2017,	the	Company	completed	the	transaction	to	acquire	Baltolink	UADBB,	a	regional	broker	based	in	Lithuania.

On	December	19,	2017,	the	Company	completed	the	transaction	to	acquire	a	client	register	of	Grant	Liddell	Financial	Advisor	Services	Pty	Ltd	in	Australia.

On	December	1,	2017,	the	Company	completed	the	transaction	to	acquire	Henderson	Insurance	Brokers	Limited,	an	independent	insurance	broking	firm	based	in	the United	Kingdom.

On	November	30,	2017,	the	Company	completed	the	transaction	to	acquire	Unidelta	AG,	an	insurance	broker	located	in	Switzerland.

On	October	31,	2017,	the	Company	completed	the	transaction	to	acquire	Unirobe	Meeùs	Groep,	an	insurance	broker	based	in	the	Netherlands.

On	October	31,	2017,	the	Company	completed	the	transaction	to	acquire	Lenzi	Paolo	Broker	di	Assicurazioni	S.r.l.,	an	insurance	broker	based	in	Italy.

On	October	26,	2017,	the	Company	completed	the	transaction	to	acquire	Nauman	Insurance	Brokers	Limited,	an	insurance	broker	based	in	New	Zealand.

On	October	2,	2017,	the	Company	completed	the	transaction	to	acquire	Portus	Consulting,	an	independent	employee	benefits	firm	based	in	the	United	Kingdom.

On	August	31,	2017,	the	Company	completed	the	transaction	to	acquire	Mark	Kelly	Insurance	and	Financial	Services	PTY	LTD,	an	Australia-based	broker	servicing	the insurance	needs	of	commercial	clients	in	and	around	the	Townsville	regional	center.

On	August	28,	2017,	the	Company	completed	the	transaction	to	acquire	a	certain	portfolio	in	the	Charlotte	office	of	The	Hays	Group,	Inc.	d/b/a	Hays	Companies.

On	July	27,	2017,	the	Company	completed	the	transaction	to	acquire	Grupo	Innovac	Sociedad	de	Correduría	de	Seguros,	S.A,	an	insurance	broker	based	in	Valencia, Spain.

On	July	3,	2017,	the	Company	completed	the	transaction	to	acquire	PWZ	AG,	an	independent	insurance	broker	based	in	Zurich,	Switzerland.

On	 May 31, 2017,	 the	 Company	 completed	 the	 transaction	 to	 acquire	 SchneiderGolling	 IFFOXX	 Assekuranzmakler	 AG and SchneiderGolling Industrie Assekuranzmaklergesellschaft	mbH	from	SchneiderGolling	Gruppe,	a	property	and	casualty	broker	based	in	Southern	Germany.

On	May	2,	2017,	the	Company	completed	the	transaction	to	acquire	cut-e	Assessment	Global	Holdings	Limited,	a	high-volume	online	psychometric	assessments provider	based	in	Ireland.

On	March	3,	2017,	the	Company	completed	the	transaction	to	acquire	Finaccord	Limited,	a	market	research,	publishing	and	consulting	company	based	in	the	United Kingdom.

On	January	19,	2017,	the	Company	completed	the	transaction	to	acquire	VERO	Management	AG,	an	insurance	broker	and	risk	advisor	based	in	Austria.

# Dispositions

The	Company	completed	four	dispositions	during	the	year	ended	December	31,	2018.	The	Company	completed	nine	dispositions	during	the	year	ended	December	31, 2017,	excluding	the	sale	of	the	Divested	Business,	and	five	dispositions	during	the	year	ended	December	31,	2016.

Total	pretax	losses,	net	of	gains,	for	the	year	ended	December	31,	2018	was	$6	million.	Total	pretax	gains,	net	of	losses,	for	the	years	ended	December	31,	2017,	and 2016,	were	$16	million	and	$39	million,	respectively.	Gains	and	losses	recognized	as	a	result	of	a	disposition	are	included	in	Other	income	(expense)	in	the	Consolidated Statements	of	Income.

During	the	third	quarter	of	2018,	Aon	disposed	of	certain	assets	and	liabilities	that	were	previously	classified	as	held	for	sale	due	to	management's	decision	to	exit certain	operations.	In	the	second	quarter	of	2018,	a	non-cash	impairment	charge	of	$176	million	was	recognized	to	write	down	the	assets	and	liabilities	to	a	fair	value less	 cost-to-sell	 of	$47	million	 and	$41	million,	respectively.	The	impairment	charge	was	recognized	in	Amortization	and	impairment	of	intangible	assets	on	the Consolidated	Statement	of	Income.	Adjustments	to	the	non-cash	impairment	charge	in	the	third	and	fourth	quarters	were	insignificant.

The	changes	in	the	net	carrying	amount	of	goodwill	for	the	years	ended	December	31,	2018	and	2017,	respectively,	are	as	follows	(in	millions):

| The	changes	in	the	net	carrying	amount	of	goodwill	for	the	years	ended	December	31,	2018	and	2017,	respectively,	are	as	follows	(in	millions): |  |
| :--- | :--- |
| Balance\tas\tof\tJanuary\t1,\t2017 | $7,410 |
| Goodwill\trelated\tto\tcurrent\tyear\tacquisitions | 619 |
| Goodwill\trelated\tto\tdisposals | (5) |
| Goodwill\trelated\tto\tprior\tyear\tacquisitions | (13) |
| Foreign\tcurrency\ttranslation | 347 |
| Balance\tas\tof\tDecember\t31,\t2017 | $8,358 |
| Goodwill\trelated\tto\tcurrent\tyear\tacquisitions | 38 |
| Goodwill\trelated\tto\tdisposals | (2) |
| Goodwill\trelated\tto\tprior\tyear\tacquisitions | 4 |
| Foreign\tcurrency\ttranslation | (227) |
| Balance\tas\tof\tDecember\t31,\t2018 | $8,171 |

Other	intangible	assets	by	asset	class	are	as	follows	(in	millions):

|  |  | 2018 |  |  | 2017 |  |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
|  | Gross\nCarrying\nAmount | Accumulated\nAmortization\tand\nImpairment | Net\nCarrying\nAmount | Gross\nCarrying\nAmount | Accumulated\nAmortization\tand\nImpairment | Net\nCarrying\nAmount |
| Customer\trelated\tand\tcontract\tbased | 2,240 | 1,444 | 796 | 2,550 | 1,415 | 1,135 |
| Tradenames | 1,027 | 740 | 287 | 1,047 | 533 | 514 |
| Technology\tand\tother | 391 | 325 | 66 | 416 | 332 | 84 |
| Total | $3,658 | $2,509 | $1,149 | $4,013 | $2,280 | $1,733 |

In	the	second	quarter	of	2017,	and	in	connection	with	the	completion	of	the	sale	of	the	Divested	Business,	the	Company	recognized	a	non-cash	impairment	charge	to	the associated	 tradenames	of	$380	million.	The	fair	value	of	the	tradenames	was	determined	using	the	Relief	from	Royalty	Method.	This	impairment	was	included	in Amortization	and	impairment	of	intangible	assets	on	the	Consolidated	Statement	of	Income.	Refer	to	Note	5	"Discontinued	Operations"	for	further	information.

Amortization	expense	and	impairment	charges	from	finite	lived	intangible	assets	were	$593	million,	$704	million,	and	$157	million	for	the	years	ended	December	31, 2018,	2017,	and	2016,	respectively.

The	estimated	future	amortization	for	finite-lived	intangible	assets	as	of	December	31,	2018	is	as	follows	(in	millions):

| For	the	years	ended | Estimated	Future<br>Amortization |
| :--- | :--- |
| 2019 | $385 |
| 2020 | 219 |
| 2021 | 126 |
| 2022 | 84 |
| 2023 | 72 |
| Thereafter | 263 |
| Total | $1,149 |

The	following	is	a	summary	of	outstanding	debt	(in	millions):

| As	of	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| 3.875%\tSenior\tNotes\tdue\tDecember\t2025 | 746 | 745 |
| 5.00%\tSenior\tNotes\tdue\tSeptember\t2020 | 599 | 598 |
| 3.50%\tSenior\tNotes\tdue\tJune\t2024 | 596 | 595 |
| 4.75%\tSenior\tNotes\tdue\tMay\t2045 | 592 | 592 |
| 2.875%\tSenior\tNotes\tdue\tMay\t2026\t(EUR\t500M) | 562 | 587 |
| 4.60%\tSenior\tNotes\tdue\tJune\t2044 | 544 | 544 |
| 8.205%\tJunior\tSubordinated\tNotes\tdue\tJanuary\t2027 | 521 | 521 |
| 2.80%\tSenior\tNotes\tdue\tMarch\t2021 | 398 | 398 |
| 4.00%\tSenior\tNotes\tdue\tNovember\t2023 | 348 | 348 |
| 4.50%\tSenior\tNotes\tdue\tDecember\t2028 | 347 | — |
| 6.25%\tSenior\tNotes\tdue\tSeptember\t2040 | 296 | 296 |
| 4.76%\tSenior\tNotes\tdue\tMarch\t2018\t(CAD\t375M) | — | 296 |
| 4.45%\tSenior\tNotes\tdue\tMay\t2043 | 246 | 246 |
| 4.25%\tSenior\tNotes\tdue\tDecember\t2042 | 198 | 197 |
| Commercial\tpaper | 250 | — |
| Other | 1 | 3 |
| Total\tdebt | 6,244 | 5,966 |
| Less:\tShort-term\tand\tcurrent\tportion\tof\tlong-term\tdebt | 251 | 299 |
| Total\tlong-term\tdebt | $5,993 | $5,667 |

# Notes

On	December	3,	2018,	Aon	Corporation	issued	$350	million	4.50%	Senior	Notes	due	December	2028.	The	Company	used	the	net	proceeds	of	the	offering	to	pay	down a	portion	of	outstanding	commercial	paper	and	for	general	corporate	purposes.

Each	of	the	notes	issued	by	Aon	plc	is	fully	and	unconditionally	guaranteed	by	Aon	Corporation,	and	each	of	the	notes	issued	by	Aon	Corporation	is	fully	and unconditionally	guaranteed	by	Aon	plc.	Refer	to	Note	19	"Guarantee	of	Registered	Securities"	for	additional	information	regarding	guarantees	of	outstanding	debt securities.	Each	of	the	notes	described	and	identified	in	the	table	above	contains	customary	representations,	warranties,	and	covenants,	and	the	Company	was	in compliance	with	all	such	covenants	as	of	December	31,	2018.

# Repayments	of	total	debt	are	as	follows	(in	millions):

| 2019 | $251 |
| :--- | :--- |
| 2020 | 600 |
| 2021 | 400 |
| 2022 | — |
| 2023 | — |
| Thereafter | 5,095 |
| Total\tRepayments | 6,346 |
| Unamortized\tdiscounts,\tpremiums,\tand\tdebt\tissuance\tcosts | (102) |
| Total\tDebt | $6,244 |

# Revolving	Credit	Facilities

As	of	December	31,	2018,	Aon	plc	had	two	primary	committed	credit	facilities	outstanding:	its	$900	million	multi-currency	U.S.	credit	facility	expiring	in	February 2021	(the	"2021	Facility")	and	its	$400	million	multi-currency	U.S.	credit	facility	expiring	in	October	2022	(the	"2022	Facility").	On	February	2,	2019,	the	Company extended	the	2021	Facility	by	one	year,	and	it	will	now	expire	in	February	2022.

Each	of	these	facilities	includes	customary	representations,	warranties,	and	covenants,	including	financial	covenants	that	require	Aon	plc	to	maintain	specified	ratios	of adjusted	consolidated	earnings	before	interest,	taxes,	depreciation,	and	amortization	("EBITDA")	to	consolidated	interest	expense	and	consolidated	debt	to	adjusted consolidated	EBITDA,	in	each	case,	tested	quarterly.	At	December	31,	2018,	Aon	plc	did	not	have	borrowings	under	either	the	2021	Facility	or	the	2022	Facility,	and was	in	compliance	with	all	covenants	contained	therein	during	the	twelve	months	ended	December	31,	2018.

# Commercial	Paper

Aon	Corporation,	a	wholly	owned	subsidiary	of	Aon	plc,	has	established	a	U.S.	commercial	paper	program,	and	Aon	plc	has	established	a	European	multi-currency commercial	paper	program	(collectively,	the	"CP	Programs").	Commercial	paper	may	be	issued	in	aggregate	principal	amounts	of	up	to	$600	million	under	the	U.S. program	and	€525	million	under	the	European	program,	not	to	exceed	the	amount	of	the	Company's	committed	credit,	which	was	$1.3	billion	at	December	31,	2018. The	U.S.	commercial	paper	program	is	fully	and	unconditionally	guaranteed	by	Aon	plc	and	the	European	commercial	paper	program	is	fully	and	unconditionally guaranteed	by	Aon	Corporation.

Commercial	paper	outstanding,	which	is	included	in	Short-term	debt	and	current	portion	of	long-term	debt	in	the	Company's	Consolidated	Statements	of	Financial Position,	is	as	follows	(in	millions):

The	weighted	average	commercial	paper	outstanding	and	its	related	interest	rates	are	as	follows:

| Years	ended	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| Weighted\taverage\tcommercial\tpaper\toutstanding | $580 | $170 |
| Weighted\taverage\tinterest\trate\tof\tcommercial\tpaper\toutstanding | 84% | 0.18% |

# 10.				Lease	Commitments

The	Company	leases	office	facilities,	equipment,	and	automobiles	under	non-cancelable	operating	leases.	These	leases	expire	at	various	dates,	may	contain	renewal	and expansion	options,	and	do	not	contain	restrictions	concerning	dividends	or	incurring	additional	debt.	In	addition	to	base	rental	costs,	occupancy	lease	agreements generally	provide	for	rent	escalations	resulting	from	increased	assessments	for	real	estate	taxes	and	other	charges.	The	total	amount	of	the	minimum	rent	is	expensed	on	a straight-line	basis	over	the	lease	term.	The	Company's	lease	obligations	are	primarily	for	the	use	of	office	space	and	certain	real-estate	properties	are	subleased	to	third parties.

Rental	expenses	(including	amounts	applicable	to	taxes,	insurance,	and	maintenance)	for	operating	leases	are	as	follows	(in	millions):

| Years	Ended	December	31 | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Rental\texpense | $374 | $377 | $358 |
| Sub\tlease\trental\tincome | (45) | (57) | (52) |
| Net\trental\texpense | $329 | $320 | $306 |

At	December	31,	2018,	future	minimum	rental	payments	required	under	operating	leases	that	have	initial	or	remaining	non-cancelable	lease	terms	in	excess	of	one	year are	as	follows	(in	millions):

| Year	Ended	December	31,	2018 | Gross	rental<br>commitments | Rentals	from	subleases | Net	rental	commitments |
| :--- | :--- | :--- | :--- |
| 2019 | $303 | $(34) | $269 |
| 2020 | 253 | (30) | 223 |
| 2021 | 221 | (30) | 191 |
| 2022 | 182 | (30) | 152 |
| 2023 | 148 | (12) | 136 |
| Thereafter | 472 | (5) | 467 |
| Total\tminimum\tpayments\trequired | $1,579 | $(141) | $1,438 |

On	December	22,	2017,	the	Tax	Reform	Act	was	enacted	into	law	and	the	new	legislation	contained	several	key	tax	provisions	that	impacted	the	Company,	including	a reduction	of	the	corporate	income	tax	rate	to	21%	effective	for	tax	years	beginning	after	December	31,	2017	and	a	one-time	mandatory	transition	tax	on	accumulated foreign	earnings	(the	"Transition	Tax"),	among	others.	Also	on	December	22,	2017,	the	Securities	and	Exchange	Commission	(the	"SEC")	staff	issued	Staff	Accounting Bulletin	No.	118	("SAB	118")	to	address	the	application	of	U.S.	GAAP	in	situations	when	a	registrant	did	not	have	the	necessary	information	available,	prepared,	or analyzed	in	reasonable	detail	to	complete	the	accounting	for	certain	income	tax	effects	of	the	Tax	Reform	Act	in	the	period	of	enactment.	SAB	118	allowed	registrants	to record	provisional	amounts	during	a	one-year	measurement	period.

In	the	fourth	quarter	of	2017,	a	net	provisional	charge	of	$345	million	was	recorded	which	included	the	Transition	Tax,	the	re-measurement	of	existing	deferred	tax balances,	as	well	as	local	country	income	taxes,	state	income	taxes	and	withholding	taxes	expected	to	be	due	upon	repatriation	of	the	earnings	subject	to	the	Transition Tax.	In	addition,	at	that	time	the	Company	was	unable	to	estimate	the	allocation	between	continuing	and	discontinued	operations	of	the	tax	benefit	from	foreign	tax credits	utilized	in	2017.

In	the	fourth	quarter	of	2018,	the	Company	finalized	its	accounting	for	enactment	date	income	tax	effects	of	the	Tax	Reform	Act	after	analyzing	guidance	issued	during the	measurement	period,	completing	its	reviews,	filing	its	tax	returns,	and	evaluating	the	local	tax	rules.

The	following	table	presents	the	impact	of	the	accounting	for	the	enactment	of	the	Tax	Reform	Act	on	income	tax	expense	(benefit)	from	continuing	operations	in	our Consolidated	Statements	of	Income	for	the	years	ended	December	31,	2018	and	2017.

| Years	ended	December	31 | 2018 | 2017 | Total |
| :--- | :--- | :--- | :--- |
| Transition\ttax\t(1) | $36 | $264 | $300 |
| Re-measurement\tof\tdeferred\ttax\tbalances\t(2) | (8) | 86 | 78 |
| Indefinite\treinvestment\tassertion\t(3) | 1 | (5) | (4) |
| Allocation\tof\ttax\tbenefit\tfrom\tforeign\ttax\tcredits\t(4) | 59 | — | 59 |
| Total\tincome\ttax\texpense\t(benefit) | $88 | $345 | $433 |

(1) Reflects	the	Transition	Tax	on	the	post-1986	earnings	and	profits	and	related	foreign	tax	credits	of	U.S.-owned	foreign	subsidiaries	as	of	November	2,	2017	and	December	31,	2017,	whichever is	higher.

(2) Reflects	the	re-measurement	of	deferred	tax	assets	and	liabilities	as	a	result	of	the	reduction	in	the	U.S.	corporate	income	tax	rate	from	35%	to	21%.

(3) Reflects	the	accrual	for	local	country	income	taxes,	state	income	taxes	and	withholding	taxes	as	a	result	of	the	change	in	its	indefinite	reinvestment	assertion	such	that	the	Company	is	generally no	longer	indefinitely	reinvested	on	the	earnings	subject	to	the	Transition	Tax.

(4) Reflects	the	allocation	of	tax	expense	from	discontinued	operations	to	continuing	operations	related	to	the	utilization	of	foreign	tax	credits	in	the	tax	year	ended	December	31,	2017.	Without	the income	from	discontinued	operations,	these	foreign	tax	credits	would	have	required	a	valuation	allowance.

The	payable	balance	for	the	Transition	Tax	was	$240	million	and	$264	million	as	of	December	31,	2018	and	2017,	respectively.	The	change	in	liability	is	primarily attributable	to	updating	the	calculations	pursuant	to	guidance	issued	during	the	measurement	period	and	cash	payments	made	during	the	year.	The	Company	has	elected to	pay	the	liability	in	installments	which	are	due	through	2024.

Other	significant	provisions	of	the	Tax	Reform	Act	that	impact	income	taxes	include:	additional	limitations	on	the	timing	of	the	deductibility	of	interest	payable	to related	and	unrelated	lenders,	further	limitations	on	the	deductibility	of	executive	compensation,	an	alternative	Base	Erosion	and	Anti-Abuse	Tax	that	limits	deductions for	certain	amounts	payable	to	foreign	affiliates,	and	an	additional	U.S.	tax	on	certain	future	foreign	subsidiary	earnings,	whether	or	not	distributed,	(i.e.,	global intangible	low-taxed	income	or	"GILTI").	The	Company	has	elected	to	account	for	GILTI	in	the	period	in	which	it	is	incurred,	and	therefore	has	not	provided	any deferred	tax	impacts	of	GILTI	in	its	consolidated	financial	statements	for	the	year	ended	December	31,	2018.

Income	before	income	tax	from	continuing	operations	and	the	provision	for	income	tax	from	continuing	operations	consist	of	the	following	(in	millions):

| Years	ended	December	31 | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Income\tbefore\tincome\ttaxes: |  |  |  |
| U.K. | $(240) | $(420) | $(201) |
| U.S. | (601) | (765) | (329) |
| Other | 2,087 | 1,870 | 1,931 |
| Total | $1,246 | $685 | $1,401 |
| Income\ttax\texpense\t(benefit): |  |  |  |
| Current: |  |  |  |
| U.K. | $21 | $1 | $(54) |
| U.S.\tfederal | 101 | 48 | 88 |
| U.S.\tstate\tand\tlocal | 35 | 18 | 7 |
| Other | 214 | 201 | 207 |
| Total\tcurrent\ttax\texpense | $371 | $268 | $248 |
| Deferred\ttax\texpense\t(benefit): |  |  |  |
| U.K. | $19 | $(5) | $59 |
| U.S.\tfederal | (165) | 12 | (110) |
| U.S.\tstate\tand\tlocal | (56) | (35) | (9) |
| Other | (23) | 10 | (40) |
| Total\tdeferred\ttax\tbenefit | $(225) | $(18) | $(100) |
| Total\tincome\ttax\texpense | $146 | $250 | $148 |

Income	before	income	taxes	shown	above	is	based	on	the	location	of	the	business	unit	to	which	such	earnings	are	attributable	for	tax	purposes.	In	addition,	because	the earnings	shown	above	may,	in	some	cases,	be	subject	to	taxation	in	more	than	one	country,	the	income	tax	provision	shown	above	as	U.K.,	U.S.	or	Other	may	not correspond	to	the	geographic	attribution	of	the	earnings.

The	Company	performs	a	reconciliation	of	the	income	tax	provisions	based	on	its	domicile	and	statutory	rate	at	each	reporting	period.	The	2018,	2017,	 and	2016 reconciliations	are	based	on	the	U.K.	statutory	corporate	tax	rate	of	19.0%,	19.3%,	 and	20.0%,	respectively.	The	reconciliation	to	the	provisions	from	continuing operations	reflected	in	the	Consolidated	Financial	Statements	is	as	follows:

| Years	ended	December	31 | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Statutory\ttax\trate | 19.0% | 19.3% | 20.0% |
| U.S.\tstate\tincome\ttaxes,\tnet\tof\tU.S.\tfederal\tbenefit | (0.4) | (1.5) | 0.4 |
| Taxes\ton\tinternational\toperations\t(1) | (7.3) | (30.3) | (12.2) |
| Nondeductible\texpenses | 2.7 | 3.4 | 1.4 |
| Adjustments\tto\tprior\tyear\ttax\trequirements | 0.9 | 2.0 | (1.2) |
| Adjustments\tto\tvaluation\tallowances | 3.8 | (1.8) | (2.2) |
| Change\tin\tuncertain\ttax\tpositions | 0.9 | 1.6 | 3.2 |
| Excess\ttax\tbenefits\trelated\tto\tshared\tbased\tcompensation\t(2) | (3.6) | (8.0) | — |
| U.S.\tTax\tReform\timpact\t(3) | 7.1 | 51.2 | — |
| Loss\ton\tdisposition | (10.2) | — | — |
| Other\t—\tnet | (1.2) | 0.6 | 1.2 |
| Effective\ttax\trate | 11.7% | 36.5% | 10.6% |

(1) The	Company	determines	the	adjustment	for	taxes	on	international	operations	based	on	the	difference	between	the	statutory	tax	rate	applicable	to	earnings	in	each	foreign	jurisdiction	and	the enacted	rate	of	19.0%,	19.3%	and	20.0%	at	December	31,	2018,	2017,	and	2016,	respectively.	The	benefit	to	the	Company's	effective	income	tax	rate	from	taxes	on	international	operations relates	to	benefits	from	lower-taxed	global	operations,	primarily	due	to	the	use	of	global	funding	structures	and	the	tax	holiday	in	Singapore.	The	impact	decreased	from	2017	to	2018	primarily as	a	result	of	the	decrease	in	the	U.S.	federal	tax	rate.

(2) With	the	adoption	of	ASU	2016-09	in	2017,	excess	tax	benefits	and	deficiencies	from	share-based	payment	transactions	are	recognized	as	income	tax	expense	or	benefit	in	the	Company's Consolidated	Statements	of	Income.

(3) The	impact	of	the	Tax	Reform	Act	including	the	Transition	Tax,	the	re-measurement	of	U.S.	deferred	tax	assets	and	liabilities	from	35%	to	21%,	withholding	tax	accruals,	and	the	allocation	of tax	benefit	between	continuing	operations	and	discontinued	operations	related	to	utilization	of	foreign	tax	credits.

# For	the	tax	impact	of	discontinued	operations,	see	Note	5	"Discontinued	Operations".

The	components	of	the	Company's	deferred	tax	assets	and	liabilities	are	as	follows	(in	millions):

| As	of	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| Deferred\ttax\tassets: |  |  |
| Net\toperating\tloss,\tcapital\tloss,\tinterest,\tand\ttax\tcredit\tcarryforwards | $563 | $362 |
| Employee\tbenefit\tplans | 351 | 424 |
| Other\taccrued\texpenses | 98 | 65 |
| Investment\tbasis\tdifferences | 28 | 35 |
| Deferred\trevenue | 29 | 20 |
| Tradename\tliability | — | 12 |
| Lease\tand\tservice\tguarantees | 5 | 6 |
| Brokerage\tfee\tarrangements | — | 4 |
| Other | 46 | 49 |
| Total | 1,120 | 977 |
| Valuation\tallowance\ton\tdeferred\ttax\tassets | (171) | (136) |
| Total | $949 | $841 |
| Deferred\ttax\tliabilities: |  |  |
| Intangibles\tand\tproperty,\tplant\tand\tequipment | $(310) | $(436) |
| Deferred\tcosts | (143) | (32) |
| Unremitted\tearnings | (30) | (39) |
| Unrealized\tforeign\texchange\tgains | (26) | (22) |
| Other\taccrued\texpenses | (36) | (12) |
| Other | (24) | (38) |
| Total | $(569) | $(579) |
| Net\tdeferred\ttax\tasset | $380 | $262 |

Deferred	income	taxes	(assets	and	liabilities	have	been	netted	by	jurisdiction)	have	been	classified	in	the	Consolidated	Statements	of	Financial	Position	as	follows	(in millions):

| As	of	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| Deferred\ttax\tassets\t—\tnon-current | $561 | $389 |
| Deferred\ttax\tliabilities\t—\tnon-current | (181) | (127) |
| Net\tdeferred\ttax\tasset | $380 | $262 |

Valuation	allowances	have	been	established	primarily	with	regard	to	the	tax	benefits	of	certain	net	operating	loss	and	capital	loss	carryforwards.		Valuation	allowances increased	by	$35	million	as	of	December	31,	2018,	when	compared	to	December	31,	2017.	The	change	is	primarily	attributable	to	capital	loss	carryforwards	generated by	the	2018	tax	loss	on	disposition	for	which	utilization	is	subject	to	limitation.

The	Company	generally	intends	to	limit	distributions	from	foreign	subsidiaries	to	earnings	previously	taxed	in	the	U.S.,	primarily	as	a	result	of	the	Transition	Tax,	or GILTI.	 	As	 of	 December	 31,	 2018,	 the	 Company	 has	 accrued	$30	million	 for	 local	 country	 income	 taxes,	 withholding	 taxes	 and	 state	 income	 taxes	 on	 those undistributed	earnings	that	are	not	indefinitely	reinvested.	The	Company	has	not	provided	for	deferred	taxes	on	outside	basis	differences	in	our	investments	in	our foreign	subsidiaries	that	are	unrelated	to	these	accumulated	undistributed	earnings,	as	these	outside	basis	differences	are	indefinitely	reinvested.	A	determination	of	the unrecognized	deferred	taxes	related	to	these	other	components	of	our	outside	basis	differences	is	not	practicable.

The	Company	had	the	following	net	operating	loss,	capital	loss,	and	interest	carryforwards	(in	millions):

| As	of	December	31 | 2018 | 2017 |
| :--- | :--- | :--- |
| U.K. |  |  |
| Operating\tloss\tcarryforwards | $541 | $675 |
| Capital\tloss\tcarryforwards | 400 | 415 |
| Interest\tcarryforwards | 53 | — |
| U.S. |  |  |
| Federal\toperating\tloss\tcarryforwards | $2 | $36 |
| Federal\tcapital\tloss\tcarryforwards\t&amp;\tcarryback | 367 | — |
| Federal\tinterest\tcarryforwards | 424 | — |
| State\toperating\tloss\tcarryforwards | $315 | $412 |
| State\tcapital\tloss\tcarryforwards\t&amp;\tcarryback | 221 | — |
| State\tinterest\tcarryforwards | 227 | — |
| Other\tNon-U.S. |  |  |
| Operating\tloss\tcarryforwards | $369 | $392 |
| Capital\tloss\tcarryforwards\t(1) | 30 | 36 |
| Interest\tcarryforwards\t(1) | 186 | 196 |

(1) Prior	to	2018,	interest	carryforwards	in	non-U.S.	jurisdictions	were	classified	within	capital	loss	carryforwards.	As	of	December	31,	2017,	$196	million	was	reclassified	from capital	loss	carryforwards	to	interest	carryforwards.

The	U.K.	operating	losses,	capital	losses,	and	interest	each	have	an	indefinite	carryforward	period.	The	federal	operating	loss	carryforwards	as	of	December	31,	2018 expire	at	various	dates	from	2034	to	2037	and	the	state	operating	losses	as	of	December	31,	2018	expire	at	various	dates	from	2019	to	2038.	The	federal	capital	losses can	be	carried	back	to	2015	or	carried	forward	until	2023.	State	capital	losses	can	be	carried	back	to	2015	in	certain	jurisdictions	or	carried	forward	until	2023.	Federal and	state	interest	carryforwards	have	indefinite	carryforward	periods.	Operating	and	capital	losses	in	other	non-U.S.	jurisdictions	have	various	carryforward	periods	and will	begin	to	expire	in	2019.	The	interest	carryforwards	in	other	non-U.S.	jurisdictions	have	indefinite	carryforward	periods.

During	2012,	the	Company	was	granted	a	tax	holiday	for	the	period	from	October	1,	2012	through	September	30,	2022,	with	respect	to	withholding	taxes	and	certain income	derived	from	services	in	Singapore.	This	tax	holiday	and	reduced	withholding	tax	rate	may	be	extended	when	certain	conditions	are	met	or	may	be	terminated early	if	certain	conditions	are	not	met.	The	benefit	realized	was	approximately	$77	million,	$45	million,	and	$46	million	during	the	years	ended	December	31,	2018, 2017,	and	2016,	respectively.	The	impact	of	this	tax	holiday	on	diluted	earnings	per	share	was	$0.31,	$0.17,	and	$0.17	during	the	years	ended	December	31,	2018,	2017, and	2016,	respectively.

# Uncertain	Tax	Positions

The	following	is	a	reconciliation	of	the	Company's	beginning	and	ending	amount	of	uncertain	tax	positions	(in	millions):

|  | 2018 | 2017 |
| :--- | :--- | :--- |
| Balance\tat\tJanuary\t1 | $280 | $278 |
| Additions\tbased\ton\ttax\tpositions\trelated\tto\tthe\tcurrent\tyear | 18 | 25 |
| Additions\tfor\ttax\tpositions\tof\tprior\tyears | 10 | 12 |
| Reductions\tfor\ttax\tpositions\tof\tprior\tyears | (24) | (26) |
| Settlements | — | (6) |
| Business\tcombinations | 1 | — |
| Lapse\tof\tstatute\tof\tlimitations | (6) | (7) |
| Foreign\tcurrency\ttranslation | — | 4 |
| Balance\tat\tDecember\t31 | $279 | $280 |

The	Company's	liability	for	uncertain	tax	positions	as	of	December	31,	2018,	2017,	 and	2016,	 includes	$228	million,	$219	million,	 and	$240	million,	respectively, related	to	amounts	that	would	impact	the	effective	tax	rate	if	recognized.	It	is	possible	that	the	amount	of	unrecognized	tax	benefits	may	change	in	the	next	twelve months;	however,	the	Company	does	not	expect	the	change	to	have	a	significant	impact	on	its	consolidated	statements	of	income	or	consolidated	balance	sheets.	These changes	may	be	the	result	of	settlements	of	ongoing	audits.	At	this	time,	an	estimate	of	the	range	of	the	reasonably	possible	outcomes	within	the	twelve	months	cannot be	made.

The	Company	recognizes	interest	and	penalties	related	to	uncertain	tax	positions	in	its	provision	for	income	taxes.	The	Company	accrued	potential	interest	and	penalties of	$22	million,	$11	million,	 and	$15	million	 in	2018,	2017,	 and	2016,	respectively.	The	Company	recorded	a	liability	for	interest	and	penalties	of	$77	million,	$55 million,	and	$48	million	as	of	December	31,	2018,	2017,	and	2016,	respectively.

The	Company	and	its	subsidiaries	file	income	tax	returns	in	their	respective	jurisdictions.	The	Company	has	substantially	concluded	all	U.S.	federal	income	tax	matters for	years	through	2007.	Material	U.S.	state	and	local	income	tax	jurisdiction	examinations	have	been	concluded	for	years	through	2005.	The	Company	has	concluded income	tax	examinations	in	its	primary	non-U.S.	jurisdictions	through	2010.

# 12.				Shareholders'	Equity

As	a	company	incorporated	in	England	and	Wales,	Aon	is	required	under	U.K.	law	to	have	available	"distributable	reserves"	to	make	share	repurchases	or	pay	dividends to	shareholders.	Distributable	reserves	may	be	created	through	the	earnings	of	the	U.K.	parent	company	and,	among	other	methods,	through	a	reduction	in	share	capital approved	 by	 the	 courts	 of	 England	 and	 Wales.	 Distributable	 reserves	 are	 not	 directly	 linked	 to	 a	 U.S.	 GAAP	 reported	 amount	 (e.g.,	 retained	 earnings).	As	 of December	31,	2018	and	2017,	the	Company	had	distributable	reserves	in	excess	of	$2.2	billion	and	$1.2	billion,	respectively.

# Ordinary	Shares

Aon	has	a	share	repurchase	program	authorized	by	the	Company's	Board	of	Directors	(the	"Repurchase	Program").	The	Repurchase	Program	was	established	in	April 2012	with	$5.0	billion	in	authorized	repurchases,	and	was	increased	by	$5.0	billion	in	authorized	repurchases	in	each	of	November	2014	and	February	2017	for	a	total	of $15.0	billion	in	repurchase	authorizations.

Under	the	Repurchase	Program,	Class	A	Ordinary	Shares	may	be	repurchased	through	the	open	market	or	in	privately	negotiated	transactions,	from	time	to	time,	based on	prevailing	market	conditions,	and	will	be	funded	from	available	capital.

|  | Twelve	months	ended	December	31 | Twelve	months	ended	December	31 |
| :--- | :--- | :--- |
|  | 2018 | 2017\t(1) |
| Shares\trepurchased | 10.0 | 18.0 |
| Average\tprice\tper\tshare | $143.94 | $133.67 |
| Costs\trecorded\tto\tretained\tearnings |  |  |
| Total\trepurchase\tcost | $1,447 | $2,403 |
| Additional\tassociated\tcosts | 7 | 12 |
| Total\tcosts\trecorded\tto\tretained\tearnings | $1,454 | $2,415 |

At	December	31,	2018,	the	remaining	authorized	amount	for	share	repurchase	under	the	Repurchase	Program	was	$4.0	billion.	Under	the	Repurchase	Program,	the Company	has	repurchased	a	total	of	118.3	million	shares	for	an	aggregate	cost	of	approximately	$11.0	billion.

Weighted	average	ordinary	shares	outstanding	are	as	follows	(in	millions):

| Years	ended	December	31 | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Basic\tweighted-average\tordinary\tshares\toutstanding | 245.2 | 258.5 | 268.1 |
| Dilutive\teffect\tof\tpotentially\tissuable\tshares | 1.8 | 2.2 | 2.2 |
| Diluted\tweighted-average\tordinary\tshares\toutstanding | 247.0 | 260.7 | 270.3 |

Potentially	issuable	shares	are	not	included	in	the	computation	of	diluted	net	income	per	share	if	its	inclusion	would	be	antidilutive.	There	were	no	shares	excluded	from the	calculation	in	2018,	2017,	or	2016.

# Dividends

# Accumulated	Other	Comprehensive	Loss

Changes	in	Accumulated	other	comprehensive	loss	by	component,	net	of	related	tax,	are	as	follows	(in	millions):

|  | Change	in	Fair	Value<br>of	Financial<br>Instruments	(1) | Foreign	Currency<br>Translation<br>Adjustments | Postretirement<br>Benefit	Obligation	(2) | Total |
| :--- | :--- | :--- | :--- | :--- |
| Balance\tat\tJanuary\t1,\t2016 | $(25) | $(771) | $(2,627) | $(3,423) |
| Other\tcomprehensive\tincome\t(loss)\tbefore\treclassifications: |  |  |  |  |
| Other\tcomprehensive\tincome\t(loss)\tbefore\treclassifications | (25) | (490) | (276) | (791) |
| Tax\tbenefit\t(expense) | 6 | (3) | 74 | 77 |
| Other\tcomprehensive\tincome\t(loss)\tbefore\treclassifications,\tnet | (19) | (493) | (202) | (714) |
| Amounts\treclassified\tfrom\taccumulated\tother\tcomprehensive\tincome\t(loss): |  |  |  |  |
| Amounts\treclassified\tfrom\taccumulated\tother\tcomprehensive\tincome\t(loss) | 10 | — | 322 | 332 |
| Tax\tbenefit\t(expense) | (3) | — | (104) | (107) |
| Amounts\treclassified\tfrom\taccumulated\tother\tcomprehensive\tincome\t(loss),\tnet | 7 | — | 218 | 225 |
| Net\tcurrent\tperiod\tother\tcomprehensive\tincome\t(loss) | (12) | (493) | 16 | (489) |
| Balance\tat\tDecember\t31,\t2016 | (37) | (1,264) | (2,611) | (3,912) |
| Other\tcomprehensive\tincome\t(loss)\tbefore\treclassifications |  |  |  |  |
| Other\tcomprehensive\tincome\t(loss)\tbefore\treclassifications | 18 | 397 | (220) | 195 |
| Tax\tbenefit\t(expense) | (3) | (5) | 55 | 47 |
| Other\tcomprehensive\tincome\t(loss)\tbefore\treclassifications,\tnet | 15 | 392 | (165) | 242 |
| Amounts\treclassified\tfrom\taccumulated\tother\tcomprehensive\tincome\t(loss) |  |  |  |  |
| Amounts\treclassified\tfrom\taccumulated\tother\tcomprehensive\tincome\t(loss) | (2) | (7) | 236 | 227 |
| Tax\tbenefit\t(expense) | (1) | — | (52) | (53) |
| Amounts\treclassified\tfrom\taccumulated\tother\tcomprehensive\tincome\t(loss),\tnet | (3) | (7) | 184 | 174 |
| Net\tcurrent\tperiod\tother\tcomprehensive\tincome\t(loss) | 12 | 385 | 19 | 416 |
| Balance\tat\tDecember\t31,\t2017 | (25) | (879) | (2,592) | (3,496) |
| \tAdoption\tof\tnew\taccounting\tguidance\t(3) | (1) | — | — | (1) |
| Balance\tat\tJanuary\t1,\t2018 | (26) | (879) | (2,592) | (3,497) |
| Other\tcomprehensive\tincome\t(loss)\tbefore\treclassifications |  |  |  |  |
| Other\tcomprehensive\tincome\t(loss)\tbefore\treclassifications | (15) | (437) | (124) | (576) |
| Tax\tbenefit\t(expense) | 18 | (3) | 28 | 43 |
| Other\tcomprehensive\tincome\t(loss)\tbefore\treclassifications,\tnet | 3 | (440) | (96) | (533) |
| Amounts\treclassified\tfrom\taccumulated\tother\tcomprehensive\tincome\t(loss) |  |  |  |  |
| Amounts\treclassified\tfrom\taccumulated\tother\tcomprehensive\tincome\t(loss) | 11 | — | 146 | 157 |
| Tax\tbenefit\t(expense) | (3) | — | (33) | (36) |
| Amounts\treclassified\tfrom\taccumulated\tother\tcomprehensive\tincome\t(loss),\tnet | 8 | — | 113 | 121 |
| Net\tcurrent\tperiod\tother\tcomprehensive\tincome\t(loss) | 11 | (440) | 17 | (412) |
| Balance\tat\tDecember\t31,\t2018 | $(15) | $(1,319) | $(2,575) | $(3,909) |

(1) Reclassifications	from	this	category	included	in	Accumulated	other	comprehensive	loss	are	recorded	in	Other	income	(expense),	Other	general	expenses,	and	Compensation	and	benefits.	See Note	15	"Derivatives	and	Hedging"	for	additional	information	regarding	the	Company's	derivative	and	hedging	activity.

(2) Reclassifications	from	this	category	included	in	Accumulated	other	comprehensive	loss	are	recorded	in	Other	income	(expense).

(3) Refer	to	Note	2	"Summary	of	Significant	Accounting	Principles	and	Practices	"	for	further	information.

# 13.				Employee	Benefits

# Defined	Contribution	Savings	Plans

Aon	maintains	defined	contribution	savings	plans	for	the	benefit	of	its	employees.	The	expense	recognized	for	these	plans	is	included	in	Compensation	and	benefits	in the	Consolidated	Statements	of	Income.	The	expense	for	the	significant	plans	in	the	U.S.,	U.K.,	Netherlands	and	Canada	is	as	follows	(in	millions):

| Years	ended	December	31 | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| U.S. | $98 | $105 | $121 |
| U.K. | 45 | 43 | 43 |
| Netherlands\tand\tCanada | 25 | 25 | 27 |
| Total | $168 | $173 | $191 |

The	 Company	 sponsors	 defined	 benefit	 pension	 and	 postretirement	 health	 and	 welfare	 plans	 that	 provide	 retirement,	 medical,	 and	 life	 insurance	 benefits.	 The postretirement	health	care	plans	are	contributory,	with	retiree	contributions	adjusted	annually,	and	the	life	insurance	and	pension	plans	are	generally	noncontributory. The	significant	U.S.,	U.K.,	Netherlands	and	Canadian	pension	plans	are	closed	to	new	entrants.

# Pension	Plans

The	following	tables	provide	a	reconciliation	of	the	changes	in	the	projected	benefit	obligations	and	fair	value	of	assets	for	the	years	ended	December	31,	2018	and	2017 and	a	statement	of	the	funded	status	as	of	December	31,	2018	and	2017,	for	the	material	U.K.,	U.S.,	and	other	major	plans,	which	are	located	in	the	Netherlands,	and Canada.	These	plans	represent	approximately	90%	of	the	Company's	projected	benefit	obligations.

|  | U.K. |  | U.S. |  | Other |  |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| (millions) | 2018 | 2017 | 2018 | 2017 | 2018 | 2017 |
| Change\tin\tprojected\tbenefit\tobligation |  |  |  |  |  |  |
| At\tJanuary\t1 | $4,893 | $4,874 | $3,155 | $2,902 | $1,401 | $1,227 |
| Service\tcost | — | — | — | — | — | — |
| Interest\tcost | 109 | 123 | 99 | 96 | 27 | 26 |
| Plan\tamendment | 13 | — | — | — | — | — |
| Settlements | (176) | (496) | — | — | — | — |
| Actuarial\tloss\t(gain) | (297) | 100 | (221) | 309 | (47) | 49 |
| Benefit\tpayments | (160) | (146) | (156) | (152) | (43) | (39) |
| Foreign\tcurrency\timpact | (253) | 438 | — | — | (67) | 138 |
| At\tDecember\t31 | $4,129 | $4,893 | $2,877 | $3,155 | $1,271 | $1,401 |
| Accumulated\tbenefit\tobligation\tat\tend\tof\tyear | $4,129 | $4,893 | $2,877 | $3,155 | $1,247 | $1,373 |
| Change\tin\tfair\tvalue\tof\tplan\tassets |  |  |  |  |  |  |
| At\tJanuary\t1 | $5,906 | $5,675 | $1,958 | $1,683 | $1,256 | $1,076 |
| Actual\treturn\ton\tplan\tassets | (125) | 274 | (141) | 308 | (19) | 70 |
| Employer\tcontributions | 97 | 86 | 135 | 119 | 20 | 21 |
| Settlements | (176) | (496) | — | — | — | — |
| Benefit\tpayments | (160) | (146) | (156) | (152) | (43) | (39) |
| Foreign\tcurrency\timpact | (317) | 513 | — | — | (59) | 128 |
| At\tDecember\t31 | $5,225 | $5,906 | $1,796 | $1,958 | $1,155 | $1,256 |
| Market\trelated\tvalue\tat\tend\tof\tyear | $5,225 | $5,906 | $1,981 | $1,926 | $1,155 | $1,256 |
| Amount\trecognized\tin\tStatement\tof\tFinancial\tPosition\tat\tDecember\t31 |  |  |  |  |  |  |
| Funded\tstatus | $1,096 | $1,013 | $(1,081) | $(1,197) | $(116) | $(145) |
| Unrecognized\tprior-service\tcost | 30 | 19 | 3 | 5 | (7) | (7) |
| Unrecognized\tloss | 1,106 | 1,217 | 1,705 | 1,701 | 440 | 459 |
| Net\tamount\trecognized | $2,232 | $2,249 | $627 | $509 | $317 | $307 |

In	September	2018,	the	Company	made	a	cash	contribution	of	$100	million	to	the	qualified	U.S.	pension	plan,	which	allowed	the	pension	contribution	tax	deduction	to be	taken	at	the	2017	federal	tax	rate	of	35%.

In	July	2017,	the	Company	made	a	non-cash	contribution	of	approximately	$80	million	to	its	U.S.	pension	plan.

Amounts	recognized	in	the	Consolidated	Statements	of	Financial	Position	consist	of	(in	millions):

|  | 2018 | 2017 | 2018 | 2017 | 2018 | 2017 |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| Prepaid\tbenefit\tcost\t(1) | $1,113 | $1,034 | $— | $— | $— | $— |
| Accrued\tbenefit\tliability\t-\tcurrent(2) | (1) | (1) | (46) | (43) | (5) | (5) |
| Accrued\tbenefit\tliability\t-\tnon-current(3) | (16) | (20) | (1,035) | (1,154) | (111) | (140) |
| Accumulated\tother\tcomprehensive\tloss | 1,136 | 1,236 | 1,708 | 1,706 | 433 | 452 |
| Net\tamount\trecognized | $2,232 | $2,249 | $627 | $509 | $317 | $307 |

(1) Included	in	Prepaid	pension

(2) Included	in	Other	current	liabilities

(3) Included	in	Pension,	other	postretirement,	and	postemployment	liabilities

Amounts	recognized	in	Accumulated	other	comprehensive	loss	(income)	that	have	not	yet	been	recognized	as	components	of	net	periodic	benefit	cost	at	December	31, 2018	and	2017	consist	of	(in	millions):

|  | 2018 | 2017 | 2018 | 2017 | 2018 | 2017 |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| Net\tloss | $1,106 | $1,217 | $1,705 | $1,701 | $440 | $459 |
| Prior\tservice\tcost\t(income) | 30 | 19 | 3 | 5 | (7) | (7) |
| Total | $1,136 | $1,236 | $1,708 | $1,706 | $433 | $452 |

In	2018,	U.S.	plans	with	a	projected	benefit	obligation	("PBO")	and	an	accumulated	benefit	obligation	("ABO")	in	excess	of	the	fair	value	of	plan	assets	had	a	PBO	of $2.9	billion,	an	ABO	of	$2.9	billion,	and	plan	assets	with	a	fair	value	of	$1.8	billion.	U.K.	plans	with	a	PBO	in	excess	of	the	fair	value	of	plan	assets	had	a	PBO	of	$47 million	and	plan	assets	with	a	fair	value	of	$30	million,	and	U.K.	plans	with	an	ABO	in	excess	of	the	fair	value	of	plan	assets	had	an	ABO	of	$47	million	and	plan assets	with	a	fair	value	of	$30	million.	Other	plans	with	a	PBO	in	excess	of	the	fair	value	of	plan	assets	had	a	PBO	of	$1.2	billion	and	plan	assets	with	a	fair	value	of $1.1	billion,	and	other	plans	with	an	ABO	in	excess	of	the	fair	value	of	plan	assets	had	an	ABO	of	$363	million	and	plan	assets	with	a	fair	value	of	$271	million.

In	2017,	U.S.	plans	with	a	PBO	and	an	ABO	in	excess	of	the	fair	value	of	plan	assets	had	a	PBO	of	$3.2	billion,	an	ABO	of	$3.2	billion,	and	plan	assets	of	$2.0	billion. U.K.	plans	with	a	PBO	in	excess	of	the	fair	value	of	plan	assets	had	a	PBO	of	$52	million	and	plan	assets	with	a	fair	value	of	$30	million,	and	plans	with	an	ABO	in excess	of	the	fair	value	of	plan	assets	had	an	ABO	of	$52	million	and	plan	assets	with	a	fair	value	of	$30	million.	Other	plans	with	a	PBO	in	excess	of	the	fair	value	of plan	assets	had	a	PBO	of	$1.4	billion	and	plan	assets	with	a	fair	value	of	$1.2	billion,	and	plans	with	an	ABO	in	excess	of	the	fair	value	of	plan	assets	had	an	ABO	of $1.3	billion	and	plan	assets	with	a	fair	value	of	$1.2	billion.

Service	cost	is	reported	in	Compensation	and	benefits	and	all	other	components	are	reported	in	Other	income	(expense)	as	follows	(in	millions):

|  |  | U.K. |  |  | U.S. |  |  | Other |  |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- | :--- |
|  | 2018 | 2017 | 2016 | 2018 | 2017 | 2016 | 2018 | 2017 | 2016 |
| Service\tcost | $— | $— | $— | $— | $— | $— | $— | $— | $— |
| Interest\tcost | 109 | 123 | 158 | 99 | 96 | 111 | 27 | 26 | 29 |
| Expected\treturn\ton\tplan\tassets,\tnet\tof\nadministration\texpenses | (192) | (199) | (243) | (144) | (140) | (156) | (45) | (47) | (48) |
| Amortization\tof\tprior-service\tcost | 1 | 1 | 2 | 2 | 2 | 2 | — | — | — |
| Amortization\tof\tnet\tactuarial\tloss | 28 | 31 | 31 | 59 | 50 | 50 | 12 | 11 | 10 |
| Net\tperiodic\tbenefit\t(income)\tcost | (54) | (44) | (52) | 16 | 8 | 7 | (6) | (10) | (9) |
| Settlement\texpense | 37 | 125 | 61 | — | — | 158 | — | — | — |
| Total\tnet\tperiodic\tbenefit\tcost\t(income) | $(17) | $81 | $9 | $16 | $8 | $165 | $(6) | $(10) | $(9) |

The	Company	uses	a	full-yield	curve	approach	in	the	estimation	of	the	service	and	interest	cost	components	of	net	periodic	pension	and	postretirement	benefit	cost	for	its major	pension	and	other	postretirement	benefit	plans;	this	was	obtained	by	applying	the	specific	spot	rates	along	the	yield	curve	used	in	the	determination	of	the	benefit obligation	to	the	relevant	projected	cash	flows.

In	March	2017,	the	Company	approved	a	plan	to	offer	a	voluntary	one-time	lump	sum	payment	option	to	certain	eligible	employees	of	the	Company's	U.K.	pension plans	that,	if	accepted,	would	settle	the	Company's	pension	obligations	to	them.	The	lump	sum	cash	payment	offer	closed	during	2018.	As	of	December	31,	2018,	lump sum	payments	from	plan	assets	of	£139	million	($176	million	using	December	31,	2018	exchange	rates)	were	paid.	As	a	result	of	this	settlement,	the	Company remeasured	the	assets	and	liabilities	of	the	U.K.	pension	plan	during	the	fourth	quarter	of	2018,	which	in	aggregate	resulted	in	a	reduction	to	the	projected	benefit obligation	of	£122	million	($154	million	using	December	31,	2018	exchange	rates)	as	well	as	a	non-cash	settlement	charge	of	£28	million	($37	million	using	average exchange	rates)	for	the	year	ended	December	31,	2018.

In	total	for	2017,	lump	sum	payments	from	plan	assets	of	£371	million	($496	million	using	December	31,	2017	exchange	rates)	were	paid.	As	a	result	of	this	settlement, the	Company	remeasured	the	assets	and	liabilities	of	the	U.K.	pension	plan	during	the	fourth	quarter	of	2017,	which	in	aggregate	resulted	in	a	reduction	to	the	projected benefit	obligation	of	£325	million	($434	million	using	December	31,	2017	exchange	rates)	as	well	as	a	non-cash	settlement	charge	of	£93	million	($125	million	using average	December	31,	2017	exchange	rate)	in	the	fourth	quarter	of	2017.

In	March	2016,	 the	Company	announced	a	plan	 to	offer	a	voluntary	one-time	 lump	sum	payment	option	 to	certain	eligible	former	employees	under	one	of	 the Company's	U.K.	pension	plans	that,	if	accepted,	would	settle	the	Company's	pension	obligations	to	them.	The	lump	sum	cash	payment	offer	closed	during	the	second quarter	of	2016.	In	total,	lump	sum	payments	from	plan	assets	of	£116	million	($159	million	using	June	30,	2016	exchange	rates)	were	paid.	As	a	result	of	this settlement,	the	Company	remeasured	the	assets	and	liabilities	of	the	U.K.	pension	plan	during	the	second	quarter	of	2016,	which	in	aggregate	resulted	in	a	reduction	to the	projected	benefit	obligation	of	£103	million	($141	million	using	June	30,	2016	Exchange	rates)	as	well	as	a	non-cash	settlement	charge	of	£42	million	($61	million using	average	June	30,	2016	exchange	rate)	in	the	second	quarter	of	2016.

In	August	2016,	the	Company	announced	a	plan	to	offer	a	voluntary	one-time	lump	sum	payment	option	to	certain	eligible	former	employees	under	one	of	the Company's	U.S.	pension	plans,	that	if	accepted,	would	settle	the	Company's	pension	obligations	to	them.	The	lump	sum	cash	payment	offer	closed	during	the	fourth quarter	of	2016.	In	total,	lump	sum	payments	from	plan	assets	of	$281	million	were	paid.	As	a	result	of	this	settlement,	the	Company	remeasured	the	assets	and liabilities	of	the	U.S.	pension	plan	during	the	fourth	quarter	of	2016,	which	in	aggregate	resulted	in	a	reduction	to	the	projected	benefit	obligation	of	$325	million	as	well as	a	non-cash	settlement	charge	of	$158	million	in	the	fourth	quarter	of	2016.

# The	weighted-average	assumptions	used	to	determine	benefit	obligations	are	as	follows:

The	amounts	in	Accumulated	other	comprehensive	loss	expected	to	be	recognized	as	components	of	net	periodic	benefit	cost	during	2019,	not	including	voluntary	one- time	lump	sum	payments,	are	$55	million	in	the	U.S.	and	$42	million	outside	the	U.S.

# Expected	Return	on	Plan	Assets

To	determine	the	expected	long-term	rate	of	return	on	plan	assets,	the	historical	performance,	investment	community	forecasts	and	current	market	conditions	are analyzed	to	develop	expected	returns	for	each	asset	class	used	by	the	plans.	The	expected	returns	for	each	asset	class	are	weighted	by	the	target	allocations	of	the	plans. The	expected	return	of	7.71%	on	U.S.	plan	assets	reflects	a	portfolio	that	is	seeking	asset	growth	through	a	higher	equity	allocation	while	maintaining	prudent	risk	levels. The	portfolio	contains	certain	assets	that	have	historically	resulted	in	higher	returns,	as	well	as	other	financial	instruments	to	minimize	downside	risk.

No	plan	assets	are	expected	to	be	returned	to	the	Company	during	2019.

# Fair	value	of	plan	assets

The	Company	determined	the	fair	value	of	plan	assets	through	numerous	procedures	based	on	the	asset	class	and	available	information.	Refer	to	Note	16	"Fair	Value Measurements	and	Financial	Instruments"	for	a	description	of	the	procedures	performed	to	determine	the	fair	value	of	the	plan	assets.

The	fair	values	of	the	Company's	U.S.	pension	plan	assets	at	December	31,	2018	and	December	31,	2017,	by	asset	category,	are	as	follows	(in	millions):

| Asset	Category | Balance	at	December	31,<br>2018 | Markets	for	Identical<br>Assets<br>(Level	1) | Significant	Other<br>Observable	Inputs<br>(Level	2) | Significant	Unobservable<br>Inputs<br>(Level	3) |
| :--- | :--- | :--- | :--- | :--- |
| Cash\tand\tcash\tequivalents\t(1) | $130 | $130 | $— | $— |
| Equity\tinvestments: |  |  |  |  |
| Large\tcap\tdomestic | 294 | 294 | — | — |
| Small\tcap\tdomestic | 14 | 14 | — | — |
| International | 76 | 76 | — | — |
| Equity\tderivatives | (14) | — | (14) | — |
| Pooled\tfunds: |  |  |  |  |
| \t\t\tInternational\t(2) | 235 | — | — | — |
| \t\t\tLarge\tcap\tdomestic\t(2) | 8 | — | — | — |
| \t\t\tSmall\tcap\tdomestic\t(2) | 42 | — | — | — |
| Fixed\tincome\tinvestments:\t(3) |  |  |  |  |
| Corporate\tbonds | 111 | — | 111 | — |
| \t\t\tGovernment\tand\tagency\tbonds | 126 | 95 | 31 | — |
| Asset-backed\tsecurities | 2 | — | 2 | — |
| Pooled\tfunds: |  |  |  |  |
| \t\t\tGovernment\tand\tagency\tbonds\t(2) | 95 | — | — | — |
| \t\t\tCorporate\tbonds\t(2) | 322 | — | — | — |
| Other\tinvestments: |  |  |  |  |
| Real\testate\tand\tREITs\t(4) | 78 | 78 | — | — |
| Alternative\tinvestments\t(2)\t(5) | 277 | — | — | — |
| Total | $1,796 | $687 | $130 | $— |

(1) Consists	of	cash	and	institutional	short-term	investment	funds.

(2) Certain	investments	measured	at	fair	value	using	the	net	asset	value	per	share	practical	expedient	have	not	been	classified	in	the	fair	value	hierarchy.	The	fair	value	amounts	presented	in	the above	table	are	intended	to	permit	reconciliation	of	the	fair	values	to	the	amounts	presented	in	the	plan	assets	contained	in	this	Note.

(3) Consists	of	corporate	and	government	bonds,	asset-backed	securities,	and	fixed-income	derivatives.

(4) Consists	of	exchange	traded	real	estate	investment	trusts	("REITs").

(5) Consists	of	limited	partnerships,	private	equity,	and	hedge	funds.

| Asset	Category | Balance	at	December	31,<br>2017 | Markets	for	Identical<br>Assets<br>(Level	1) | Significant	Other<br>Observable	Inputs<br>(Level	2) | Significant	Unobservable<br>Inputs<br>(Level	3) |
| :--- | :--- | :--- | :--- | :--- |
| Cash\tand\tcash\tequivalents\t(1) | $56 | $56 | $— | $— |
| Equity\tinvestments: |  |  |  |  |
| Large\tcap\tdomestic | 313 | 313 | — | — |
| Small\tcap\tdomestic | 17 | 17 | — | — |
| International | 90 | 90 | — | — |
| Equity\tderivatives | 111 | — | 111 | — |
| \t\tPooled\tfunds: |  |  |  |  |
| \t\t\t\tInternational\t(2) | 270 | — | — | — |
| \t\t\t\tLarge\tcap\tdomestic\t(2) | 12 | — | — | — |
| \t\t\t\tSmall\tcap\tdomestic\t(2) | 114 | — | — | — |
| Fixed\tincome\tinvestments:\t(3) |  |  |  |  |
| Corporate\tbonds | 110 | — | 110 | — |
| Government\tand\tagency\tbonds | 148 | 114 | 34 | — |
| Pooled\tfunds: |  |  |  |  |
| \t\t\tCorporate\tbonds\t(2) | 290 | — | — | — |
| Other\tinvestments: |  |  |  |  |
| Real\testate\tand\tREITs\t(4) | 82 | 82 | — | — |
| Alternative\tinvestments\t(2)\t(5) | 345 | — | — | — |
| Total | $1,958 | $672 | $255 | $— |

(4) Consists	of	exchange	traded	REITs.

The	fair	values	of	the	Company's	major	U.K.	pension	plan	assets	at	December	31,	2018	and	December	31,	2017,	by	asset	category,	are	as	follows	(in	millions):

|  | Balance	at	December	31,<br>2018 | Markets	for	Identical<br>Assets<br>(Level	1) | Significant	Other<br>Observable	Inputs<br>(Level	2) | Significant	Unobservable<br>Inputs<br>(Level	3) |
| :--- | :--- | :--- | :--- | :--- |
| Cash\tand\tcash\tequivalents\t(1) | $96 | $96 | $— | $— |
| Equity\tinvestments: |  |  |  |  |
| \t\tPooled\tfunds: |  |  |  |  |
| \t\tGlobal\t(2) | 209 | — | — | — |
| \t\tEurope\t(2) | 3 | — | — | — |
| Fixed\tincome\tinvestments:\t(3) |  |  |  |  |
| \t\tDerivatives\t(4) | (949) | — | (949) | — |
| \t\tFixed\tincome\tsecurities\t(5) | 2,446 | 2,079 | 367 | — |
| \t\tAnnuities | 1,688 | — | — | 1,688 |
| \t\tPooled\tfunds: |  |  |  |  |
| \t\t\t\tDerivatives\t(2) | 39 | — | — | — |
| \t\tFixed\tincome\tsecurities\t(2) | 850 | — | — | — |
| Other\tinvestments: |  |  |  |  |
| \t\tReal\testate\t(2)\t(6) | 149 | — | — | — |
| \t\tAlternative\tinvestments\t(2)\t(7) | 694 | — | — | — |
| Total | $5,225 | $2,175 | $(582) | $1,688 |

(3) Consists	of	various	equity,	fixed	income,	commodity,	and	real	estate	mutual	fund	type	investment	vehicles.

(4) Consists	of	equity	securities	and	equity	derivatives,	including	repurchase	agreements.

(5) Consists	of	corporate	and	government	bonds.

(6) Consists	of	property	funds	and	trusts	holding	direct	real	estate	investments.

|  | Balance	at	December	31,<br>2017 | Markets	for	Identical<br>Assets<br>(Level	1) | Significant	Other<br>Observable	Inputs<br>(Level	2) | Significant	Unobservable<br>Inputs<br>(Level	3) |
| :--- | :--- | :--- | :--- | :--- |
| Cash\tand\tcash\tequivalents\t(1) | $209 | $209 | $— | $— |
| Equity\tinvestments: |  |  |  |  |
| \t\tPooled\tfunds: |  |  |  |  |
| \t\tGlobal\t(2) | 401 | — | — | — |
| \t\tEurope\t(2) | 6 | — | — | — |
| Fixed\tincome\tinvestments:\t(3) |  |  |  |  |
| \t\tDerivatives\t(4) | (771) | — | (771) | — |
| \t\tFixed\tincome\tsecurities\t(5) | 2,787 | 2,362 | 425 | — |
| Annuities | 1,909 | — | — | 1,909 |
| \t\tPooled\tfunds: |  |  |  |  |
| \t\t\t\tDerivatives\t(2) | 57 | — | — | — |
| \t\t\t\tFixed\tincome\tsecurities\t(2) | 251 | — | — | — |
| Other\tinvestments: |  |  |  |  |
| \t\tReal\testate\t(2)\t(6) | 146 | — | — | — |
| Alternative\tinvestments\t(2)\t(7) | 911 | — | — | — |
| \t\tTotal | $5,906 | $2,571 | $(346) | $1,909 |

The following table	 presents the	 changes in the	 Level	 3 fair-value	 category in the	 Company's	 U.K.	 pension	 plans for the	 years	 ended	 December	 31,	2018	 and December	31,	2017	(in	millions):

The	fair	values	of	the	Company's	other	major	pension	plan	assets	at	December	31,	2018	and	December	31,	2017,	by	asset	category,	are	as	follows	(in	millions):

|  | Balance	at	December	31,<br>2018 | Markets	for	Identical<br>Assets<br>(Level	1) | Significant	Other<br>Observable	Inputs<br>(Level	2) | Significant	Unobservable<br>Inputs<br>(Level	3) |
| :--- | :--- | :--- | :--- | :--- |
| Cash\tand\tcash\tequivalents | $10 | $10 | $— | $— |
| Equity\tinvestments: |  |  |  |  |
| \t\t\tPooled\tfunds: |  |  |  |  |
| \t\tGlobal\t(1) | 281 | — | — | — |
| Fixed\tincome\tinvestments: |  |  |  |  |
| \t\t\tDerivatives\t(2) | 9 | — | 9 | — |
| \t\t\tPooled\tfunds: |  |  |  |  |
| \t\t\tFixed\tincome\tsecurities\t(1) | 766 | — | — | — |
| \t\t\tDerivatives\t(1)(2) | 16 | — | — | — |
| Other\tinvestments: |  |  |  |  |
| \t\t\tAlternative\tinvestments\t(1)\t(3) | 63 | — | — | — |
| \t\t\tPooled\tfunds: |  |  |  |  |
| \t\t\tREITs\t(1)\t(4) | 10 | — | — | — |
| Total | $1,155 | $10 | $9 | $— |

(2) Consists	of	corporate	and	government	bonds	and	fixed-income	derivatives.

|  | Balance	at	December	31,<br>2017 | Markets	for	Identical<br>Assets<br>(Level	1) | Significant	Other<br>Observable	Inputs<br>(Level	2) | Significant	Unobservable<br>Inputs<br>(Level	3) |
| :--- | :--- | :--- | :--- | :--- |
| Cash\tand\tcash\tequivalents | $11 | $11 | $— | $— |
| Equity\tinvestments: |  |  |  |  |
| \t\t\tPooled\tfunds: |  |  |  |  |
| \t\tGlobal\t(1) | 370 | — | — | — |
| \t\tNorth\tAmerica\t(1) | 26 | — | — | — |
| Fixed\tincome\tinvestments: |  |  |  |  |
| \t\t\tFixed\tincome\tsecurities\t(2) | 211 | — | 211 | — |
| \t\t\tDerivatives\t(2) | 40 | — | 40 | — |
| \t\t\tPooled\tfunds: |  |  |  |  |
| \t\t\tFixed\tincome\tsecurities\t(1) | 566 | — | — | — |
| Other\tinvestments: |  |  |  |  |
| \t\t\tAlternative\tinvestments\t(1)\t(3) | 26 | — | — | — |
| \t\t\tPooled\tfunds: |  |  |  |  |
| \t\t\tREITs\t(1)\t(4) | 6 | — | — | — |
| Total | $1,256 | $11 | $251 | $— |

# Investment	Policy	and	Strategy

The	U.S.	investment	policy,	as	established	by	the	Aon	Retirement	Plan	Governance	and	Investment	Committee	("RPGIC"),	seeks	reasonable	asset	growth	at	prudent	risk levels	within	target	allocations,	which	are	50%	equity	investments,	27%	fixed	income	investments,	and	23%	other	investments.	Aon	believes	that	plan	assets	are	well- diversified	and	are	of	appropriate	quality.	The	investment	portfolio	asset	allocation	is	reviewed	quarterly	and	re-balanced	to	be	within	policy	target	allocations.	The investment	policy	 is	reviewed	at	 least	annually	and	revised,	as	deemed	appropriate	by	 the	RPGIC.	The	 investment	policies	for	 international	plans	are	generally established	by	the	local	pension	plan	trustees	and	seek	to	maintain	the	plans'	ability	to	meet	liabilities	and	to	comply	with	local	minimum	funding	requirements.	Plan assets	are	invested	in	diversified	portfolios	that	provide	adequate	levels	of	return	at	an	acceptable	level	of	risk.	The	investment	policies	are	reviewed	at	least	annually and	revised,	as	deemed	appropriate	to	ensure	that	the	objectives	are	being	met.	At	December	31,	2018,	the	weighted	average	targeted	allocation	for	the	U.K.	and	non- U.S.	plans	was	12%	for	equity	investments,	79%	for	fixed	income	investments,	and	9%	for	other	investments.

# Cash	Flows

# Contributions

Based	 on	 current	 assumptions,	 in	2019,	 the	 Company	 expects to	 contribute	 approximately	$80	million,	$46	million, and	$19	million to its	 U.K.,	 U.S.	 and	 other significant	international	pension	plans,	respectively.

# Estimated	Future	Benefit	Payments

Estimated	future	benefit	payments	for	plans,	not	including	voluntary	one-time	lump	sum	payments,	are	as	follows	at	December	31,	2018	(in	millions):

|  | U.K. | U.S. | Other |
| :--- | :--- | :--- | :--- |
| 2019 | $137 | $178 | $42 |
| 2020 | 139 | 182 | 43 |
| 2021 | 144 | 185 | 44 |
| 2022 | 149 | 187 | 45 |
| 2023 | 152 | 177 | 46 |
| 2024\t–\t2028 | 795 | 879 | 248 |

# U.S.	and	Canadian	Other	Postretirement	Benefits

The	following	table	provides	an	overview	of	the	accumulated	projected	benefit	obligation,	fair	value	of	plan	assets,	funded	status	and	net	amount	recognized	as	of December	31,	2018	and	2017	for	the	Company's	other	significant	postretirement	benefit	plans	located	in	the	U.S.	and	Canada	(in	millions):

|  | 2018 | 2017 |
| :--- | :--- | :--- |
| Accumulated\tprojected\tbenefit\tobligation | $91 | $99 |
| Fair\tvalue\tof\tplan\tassets | 14 | 17 |
| Funded\tstatus | (77) | (82) |
| Unrecognized\tprior-service\tcredit | (1) | (1) |
| Unrecognized\t(gain)\tloss | (6) | (3) |
| Net\tamount\trecognized | $(84) | $(86) |

Other	information	related	to	the	Company's	other	postretirement	benefit	plans	are	as	follows:

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Net\tperiodic\tbenefit\tcost\trecognized\t(millions) | $3 | $1 | $5 |
| Weighted-average\tdiscount\trate\tused\tto\tdetermine\tfuture\tbenefit\tobligations | 3.91\t-\t4.26% | 3.32\t-\t3.64% | 3.71\t-\t4.15% |
| Weighted-average\tdiscount\trate\tused\tto\tdetermine\tnet\tperiodic\tbenefit\tcosts | 3.32\t-\t3.64% | 3.71\t-\t4.15% | 3.99\t-\t4.33% |

Amounts	recognized	in	Accumulated	other	comprehensive	income	that	have	not	yet	been	recognized	as	components	of	net	periodic	benefit	cost	at	December	31,	2018 are	$1	million	and	$6	million	of	prior	service	credit	and	net	gain,	respectively.	The	amount	in	Accumulated	other	comprehensive	income	expected	to	be	recognized	as	a component	of	net	periodic	benefit	cost	during	2019	is	$1.7	million	and	$0.1	million	of	net	gain	and	prior	service	credit,	respectively.

Based	on	current	assumptions,	the	Company	expects:

•To	 contribute	$5	million to fund	 significant	 other	 postretirement	 benefit	 plans	 during 2019.

•Estimated	future	benefit	payments	will	be	approximately	$5	million	each	year	for	2019	through	2023,	and	$25	million	in	aggregate	for	2024- 2028.

The	accumulated	postretirement	benefit	obligation	is	increased	by	$5	million	and	decreased	by	$5	million	by	a	respective	1%	increase	or	decrease	to	the	assumed	health care	trend	rate.	The	service	cost	and	interest	cost	components	of	net	periodic	benefits	cost	is	increased	by	$0.5	million	and	decreased	by	$0.4	million	by	a	respective	1% increase	or	decrease	to	the	assumed	health	care	trend	rate.

For	most	of	the	participants	in	the	U.S.	plan,	Aon's	liability	for	future	plan	cost	increases	for	pre-65	and	Medical	Supplement	plan	coverage	is	limited	to	5%	per	annum. Although	the	net	employer	trend	rates	range	from	4%	to	7%	per	year,	because	of	this	cap,	these	plans	are	effectively	limited	to	5%	per	year	in	the	future.

# 14.				Share-Based	Compensation	Plans

The	following	table	summarizes	share-based	compensation	expense	recognized	in	the	Consolidated	Statements	of	Income	in	Compensation	and	benefits	(in	millions):

| Years	ended	December	31 | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Restricted\tshare\tunits\t("RSUs") | $186 | $182 | $176 |
| Performance\tshare\tawards\t("PSAs") | 143 | 127 | 120 |
| Employee\tshare\tpurchase\tplans | 9 | 10 | 10 |
| Total\tshare-based\tcompensation\texpense | 338 | 319 | 306 |
| Tax\tbenefit | 74 | 73 | 90 |
| Share-based\tcompensation\texpense,\tnet\tof\ttax | $264 | $246 | $216 |

RSUs	generally	vest	between	three	and	five	years.	The	fair	value	of	RSUs	is	based	upon	the	market	value	of	Aon	plc	ordinary	shares	at	the	date	of	grant.	With	certain limited	exceptions,	any	break	in	continuous	employment	will	cause	the	forfeiture	of	all	non-vested	awards.	Compensation	expense	associated	with	RSUs	is	recognized on	a	straight-line	basis	over	the	requisite	service	period.	Dividend	equivalents	are	paid	on	certain	RSUs,	based	on	the	initial	grant	amount.

The	following	table	summarizes	the	status	of	the	Company's	RSUs,	including	shares	related	to	the	Divested	Business	(shares	in thousands,	except	fair	value):

| Years	ended	December	31 | Shares | Fair	Value	at	Date<br>of	Grant | Shares | Fair	Value	at	Date<br>of	Grant | Shares | Fair	Value	at	Date<br>of	Grant |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| Non-vested\tat\tbeginning\tof\tyear | 4,849 | $104 | 6,195 | $89 | 7,167 | $77 |
| Granted | 1,500 | 141 | 1,700 | 123 | 2,252 | 101 |
| Vested | (1,943) | 97 | (2,407) | 82 | (2,845) | 70 |
| Forfeited | (198) | 114 | (639) | 93 | (379) | 82 |
| Non-vested\tat\tend\tof\tyear | 4,208 | $120 | 4,849 | $104 | 6,195 | $89 |

Unamortized	deferred	compensation	expense	was	$346	million	as	of	December	31,	2018,	with	a	remaining	weighted-average	amortization	period	of	approximately	2.1 years.

The	vesting	of	PSAs	is	contingent	upon	meeting	a	cumulative	level	of	earnings	per	share	related	performance	over	a	three-year	period.	The	actual	issue	of	shares	may range	from	0-200%	of	the	target	number	of	PSAs	granted,	based	on	the	terms	of	the	plan	and	level	of	achievement	of	the	related	performance	target.	The	grant	date	fair value	of	PSAs	is	based	upon	the	market	price	of	Aon	plc	ordinary	shares	at	the	date	of	grant.	The	performance	conditions	are	not	considered	in	the	determination	of	the grant	date	fair	value	for	these	awards.	Compensation	expense	is	recognized	over	the	performance	period	based	on	management's	estimate	of	the	number	of	units expected	to	vest.	Management	evaluates	its	estimate	of	the	actual	number	of	shares	expected	to	be	issued	at	the	end	of	the	programs	on	a	quarterly	basis.	The	cumulative effect	of	the	change	in	estimate	is	recognized	in	the	period	of	change	as	an	adjustment	to	Compensation	and	benefits	expense	in	the	Consolidated	Statements	of	Income, if	necessary.	Dividend	equivalents	are	not	paid	on	PSAs.

The	following	table	summarizes	the	Company's	target	PSAs	granted	and	shares	that	would	be	issued	at	current	performance	levels	for	PSAs	granted	during	the	years ended	December	31,	2018,	2017,	and	2016	(shares	in	thousands	and	dollars	in	millions,	except	fair	value):

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Target\tPSAs\tgranted\tduring\tperiod | 564 | 548 | 750 |
| Weighted\taverage\tfair\tvalue\tper\tshare\tat\tdate\tof\tgrant | $134 | $114 | $100 |
| Number\tof\tshares\tthat\twould\tbe\tissued\tbased\ton\tcurrent\tperformance\tlevels | 840 | 1,068 | 1,122 |
| Unamortized\texpense,\tbased\ton\tcurrent\tperformance\tlevels | $81 | $44 | $— |

During	2018,	the	Company	issued	approximately	1.0	million	shares	in	connection	with	performance	achievements	related	to	the	2015-2017	Leadership	Performance Plan	("LPP")	cycle.	During	2017,	the	Company	issued	approximately	0.9	million	shares	in	connection	with	performance	achievements	related	to	the	2014-2016	LPP cycle.	During	2016,	the	Company	issued	approximately	1.3	million	shares	in	connection	with	performance	achievements	related	to	the	2013-2015	LPP	cycle.

# 15.				Derivatives	and	Hedging

The	Company	is	exposed	to	market	risks,	including	changes	in	foreign	currency	exchange	rates	and	interest	rates.	To	manage	the	risk	related	to	these	exposures,	the Company	enters	into	various	derivative	instruments	that	reduce	these	risks	by	creating	offsetting	exposures.	The	Company	does	not	enter	into	derivative	transactions	for trading	or	speculative	purposes.

# Foreign	Exchange	Risk	Management

The	Company	is	exposed	to	foreign	exchange	risk	when	it	earns	revenues,	pays	expenses,	enters	into	monetary	intercompany	transfers	or	other	transactions	denominated in	a	currency	that	differs	from	its	functional	currency.	The	Company	uses	foreign	exchange	derivatives,	typically	forward	contracts,	options	and	cross-currency	swaps, to	reduce	its	overall	exposure	to	the	effects	of	currency	fluctuations	on	cash	flows.	These	exposures	are	hedged,	on	average,	for	less	than	two	years.	These	derivatives	are accounted	for	as	hedges,	and	changes	in	fair	value	are	recorded	each	period	in	Other	comprehensive	income	(loss)	in	the	Consolidated	Statements	of	Comprehensive Income.

The	Company	also	uses	foreign	exchange	derivatives,	typically	forward	contracts	and	options,	to	economically	hedge	the	currency	exposure	of	the	Company's	global liquidity	profile,	including	monetary	assets	or	liabilities	that	are	denominated	in	a	non-functional	currency	of	an	entity,	typically	on	a	rolling	30-day	basis,	but	may	be for	up	to	one	year	in	the	future.	These	derivatives	are	not	accounted	for	as	hedges,	and	changes	in	fair	value	are	recorded	each	period	in	Other	income	(expense)	in	the Consolidated	Statements	of	Income.

The	notional	and	fair	values	of	derivative	instruments	are	as	follows	(in	millions):

|  |  |  | Net	Amount	of	Derivative	Assets | Net	Amount	of	Derivative	Assets | Net	Amount	of	Derivative	Liabilities |  |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
|  | Notional\tAmount |  | Presented\tin\tthe\tStatements\tof\tFinancial\nPosition\t(1) | Presented\tin\tthe\tStatements\tof\tFinancial\nPosition\t(1) | Presented\tin\tthe\tStatements\tof\tFinancial\nPosition\t(2) | Presented\tin\tthe\tStatements\tof\tFinancial\nPosition\t(2) |
| As\tof\tDecember\t31 | 2018 | 2017 | 2018 | 2017 | 2018 | 2017 |
| Foreign\texchange\tcontracts |  |  |  |  |  |  |
| \t\tAccounted\tfor\tas\thedges | $646 | $701 | $17 | $31 | $2 | $3 |
| \t\tNot\taccounted\tfor\tas\thedges\t(3) | 269 | 254 | 1 | 1 | 6 | 3 |
| Total | $915 | $955 | $18 | $32 | $8 | $6 |

(3) These	contracts	typically	are	for	30-day	durations	and	executed	close	to	the	last	day	of	the	most	recent	reporting	month,	thereby	resulting	in	nominal	fair	values	at	the	balance	sheet	date.

The	amounts	of	derivative	gains	(losses)	recognized	in	the	Consolidated	Financial	Statements	are	as	follows	(in	millions):

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Gain\t(Loss)\trecognized\tin\tAccumulated\tother\tcomprehensive\tloss | $(18) | $18 | $(25) |
| Location\tof\tfuture\treclassification\tfrom\tAccumulated\tother\tcomprehensive\tloss |  |  |  |
| Compensation\tand\tbenefits | $(5) | $12 | $8 |
| Other\tgeneral\texpenses | $3 | $4 | $(13) |
| Other\tincome\t(expense)\t(1) | $(16) | $2 | $(20) |

(1) With	the	adoption	of	new	derivative	guidance	in	2019,	gains	(losses)	on	derivatives	accounted	for	as	hedges	will	be	recognized	in	Total	revenue	in	the	Company's	Consolidated	Statements	of Income	rather	than	Other	income	(expense).	Refer	to	Note	2	"Summary	of	Significant	Accounting	Principles	and	Practices"	for	additional	details.

The	amounts	of	derivative	gains	(losses)	reclassified	from	Accumulated	other	comprehensive	loss	into	Consolidated	Statements	of	Income	(effective	portion)	are	as follows	(in	millions):

|  | 2018 | 2017 | 2016 |
| :--- | :--- | :--- | :--- |
| Compensation\tand\tbenefits | $1 | $14 | $2 |
| Other\tgeneral\texpenses | (2) | (5) | (4) |
| Interest\texpense | (2) | (1) | (1) |
| Other\tincome\t(expense) | (8) | (9) | (7) |
| Total | $(11) | $(1) | $(10) |

The	Company	estimates	that	approximately	$13	million	of	pretax	losses	currently	included	within	Accumulated	other	comprehensive	loss	will	be	reclassified	in	to earnings	in	the	next	twelve	months.

The	amount	of	gain	(loss)	recognized	in	income	on	the	ineffective	portion	of	derivatives	for	2018,	2017,	and	2016	was	insignificant.

The	Company	recorded	a	loss	of	$27	million	for	2018,	a	gain	of	$7	million	in	2017,	and	an	insignificant	loss	in	2016	in	Other	income	(expense)	for	foreign	exchange derivatives	not	designated	or	qualifying	as	hedges.

# Net	Investments	in	Foreign	Operations	Risk	Management

The	Company	uses	non-derivative	financial	instruments	to	protect	the	value	of	its	investments	in	a	number	of	foreign	subsidiaries.	In	2016,	the	Company	designated	a portion	of	its	euro-denominated	commercial	paper	issuances	as	a	non-derivative	hedge	of	the	foreign	currency	exposure	of	a	net	investment	in	its	European	operations. The	change	in	fair	value	of	the	designated	portion	of	the	euro-denominated	commercial	paper	due	to	changes	in	foreign	currency	exchange	rates	is	recorded	in	Foreign currency	translation	adjustment,	a	component	of	Accumulated	other	comprehensive	loss,	to	the	extent	it	is	effective	as	a	hedge.	The	foreign	currency	translation adjustment	 of	 the	 hedged	 net	 investments	 is	 also	 recorded	 in	Accumulated	 other	 comprehensive	 loss.	 Ineffective	 portions	 of	 net	 investment	 hedges,	 if	 any,	 are reclassified	from	Accumulated	other	comprehensive	loss	into	earnings	during	the	period	of	change.

As	of	December	31,	2018,	the	Company	has	€220	million	($250	million	at	December	31,	2018	exchange	rates)	of	outstanding	euro-denominated	commercial	paper designated	as	a	hedge	of	the	foreign	currency	exposure	of	its	net	investment	in	its	European	operations.	As	of	December	31,	2018,	the	unrealized	gain	recognized	in Accumulated	other	comprehensive	loss	related	to	the	net	investment	non	derivative	hedging	instrument	was	$21	million.

The	Company	did	not	reclassify	any	deferred	gains	or	losses	related	to	net	investment	hedges	from	Accumulated	other	comprehensive	loss	to	earnings	for	2018,	2017 and	2016.	In	addition,	the	Company	did	not	incur	any	ineffectiveness	related	to	net	investment	hedges	during	2018,	2017	and	2016.

# 16.				Fair	Value	Measurements	and	Financial	Instruments

Accounting	standards	establish	a	three	tier	fair	value	hierarchy	that	prioritizes	the	inputs	used	in	measuring	fair	values	as	follows:

•Level	 1	 —	 observable inputs such	 as	 quoted	 prices for identical	 assets in	 active markets;

•Level	2	—	inputs	other	than	quoted	prices	for	identical	assets	in	active	markets,	that	are	observable	either	directly	or	indirectly; and

•Level	 3	 —	 unobservable inputs in	 which there is little	 or	 no	 market	 data	 which requires the	 use	 of	 valuation techniques	 and the	 development	 of assumptions.

The	following	methods	and	assumptions	are	used to	estimate the	fair	values	of the	Company's	financial instruments, including	pension	assets	(refer to	Note	13 "Employee	Benefits"):

Money	market	funds	consist	of	institutional	prime,	treasury,	and	government	money	market	funds.	The	Company	reviews	treasury	and	government	money	market funds	to	obtain	reasonable	assurance	that	the	fund	net	asset	value	is	$1	per	share,	and	reviews	the	floating	net	asset	value	of	institutional	prime	money	market	funds	for reasonableness.

Cash	and	cash	equivalents	consist	of	cash	and	institutional	short-term	investment	funds.	The	Company	reviews	the	short-term	investment	funds	to	obtain	reasonable assurance	that	the	fund	net	asset	value	is	$1	per	share.

Equity	investments	consist	of	domestic	and	international	equity	securities	and	equity	derivatives	valued	using	the	closing	stock	price	on	a	national	securities exchange.	Over	the	counter	equity	derivatives	are	valued	using	observable	inputs	such	as	underlying	prices	of	the	underlying	security	and	volatility.	On	a	sample	basis the	Company	reviews	the	listing	of	Level	1	equity	securities	in	the	portfolio	and	agrees	the	closing	stock	prices	to	a	national	securities	exchange,	and	independently verifies	the	observable	inputs	for	Level	2	equity	derivatives	and	securities.

Fixed	income	investments	consist	of	certain	categories	of	bonds	and	derivatives.	Corporate,	government,	and	agency	bonds	are	valued	by	pricing	vendors	who estimate	fair	value	using	recently	executed	transactions	and	proprietary	models	based	on	observable	inputs,	such	as	interest	rate	spreads,	yield	curves,	and	credit	risk. Asset-backed	securities	are	valued	by	pricing	vendors	who	estimate	fair	value	using	discounted	cash	flow	models	utilizing	observable	inputs	based	on	trade	and	quote activity	of	securities	with	similar	features.	Fixed	income	derivatives	are	valued	by	pricing	vendors	using	observable	inputs	such	as	interest	rates	and	yield	curves.	The Company	obtains	an	understanding	of	 the	models,	 inputs,	and	assumptions	used	 in	developing	prices	provided	by	 its	vendors	 through	discussions	with	 the	fund managers.	The	Company	independently	verifies	the	observable	inputs,	as	well	as	assesses	assumptions	used	for	reasonableness	based	on	relevant	market	conditions	and internal	Company	guidelines.	If	an	assumption	is	deemed	unreasonable,	based	on	the	Company's	guidelines,	it	is	then	reviewed	by	management	and	the	fair	value estimate	provided	by	the	vendor	is	adjusted,	if	deemed	appropriate.	These	adjustments	do	not	occur	frequently	and	historically	are	not	material	to	the	fair	value	estimates used	in	the	Consolidated	Financial	Statements.

Pooled	funds	consist	of	various	equity,	fixed	income,	commodity,	and	real	estate	mutual	fund	type	investment	vehicles.	Pooled	investment	funds	fair	value	is estimated	based	on	the	proportionate	share	ownership	in	the	underlying	net	assets	of	the	investment,	which	is	based	on	the	fair	value	of	the	underlying	securities	that trade	on	a	national	securities	exchange.	The	Company	gains	an	understanding	of	the	investment	guidelines	and	valuation	policies	of	the	fund	and	discusses	fund performance	with	pooled	fund	managers.	The	Company	obtains	audited	fund	manager	financial	statements,	when	available.	If	the	pooled	fund	is	designed	to	replicate	a publicly	traded	index,	the	Company	compares	the	performance	of	the	fund	to	the	index	to	assess	the	reasonableness	of	the	fair	value	measurement.

Alternative	investments	consist	of	limited	partnerships,	private	equity,	and	hedge	funds.	Alternative	investment	fair	value	is	generally	estimated	based	on	the proportionate	share	ownership	in	the	underlying	net	assets	of	the	investment	as	determined	by	the	general	partner	or	investment	manager.	The	valuations	are	based	on various	factors	depending	on	investment	strategy,	proprietary	models,	and	specific	financial	data	or	projections.	The	Company	obtains	audited	fund	manager	financial statements,	when	available.	The	Company	obtains	a	detailed	understanding	of	the	models,	inputs,	and	assumptions	used	in	developing	prices	provided	by	the	investment managers	(or	appropriate	party)	through	regular	discussions.	The	Company	also	obtains	the	investment	manger's	valuation	policies	and	assesses	the	assumptions	used for	reasonableness	based	on	relevant	market	conditions	and	internal	Company	guidelines.	If	an	assumption	is	deemed	unreasonable,	based	on	the	Company's	guidelines, it	is	then	reviewed	by	management	and	the	fair	value	estimate	provided	by	the	vendor	is	adjusted,	if	deemed	appropriate.	These	adjustments	do	not	occur	frequently	and historically	are	not	material	to	the	fair	value	estimates	in	the	Consolidated	Financial	Statements.

Derivatives	are	carried	at	fair	value,	based	upon	industry	standard	valuation	techniques	that	use,	where	possible,	current	market-based	or	independently	sourced pricing	inputs,	such	as	interest	rates,	currency	exchange	rates,	or	implied	volatilities.

Annuity	contracts	consist	of	insurance	group	annuity	contracts	purchased	to	match	the	pension	benefit	payment	stream	owed	to	certain	selected	plan	participant demographics	within	a	few	major	U.K.	defined	benefit	plans.	Annuity	contracts	are	valued	using	a	discounted	cash	flow	model	utilizing	assumptions	such	as	discount rate,	mortality,	and	inflation.

Real	estate	and	REITs	consist	of	publicly	traded	real	estate	investment	trusts	("REITs")	and	direct	real	estate	investments.	Level	1	REITs	are	valued	using	the closing	stock	price	on	a	national	securities	exchange.	Non	Level	1	values	are	based	on	the	proportionate	share	of	ownership	in	the	underlying	net	asset	value	as determined	by	the	investment	manager.	The	Company	independently	reviews	the	listing	of	Level	1	REIT	securities	in	the	portfolio	and	agrees	the	closing	stock	prices	to a	national	securities	exchange.	The	Company	gains	an	understanding	of	the	investment	guidelines	and	valuation	policies	of	the	non	Level	1	real	estate	funds	and discusses	performance	with	the	fund	managers.	The	Company	obtains	audited	fund	manager	financial	statements,	when	available.	See	the	description	of	"Alternative investments"	for	further	detail	on	valuation	procedures	surrounding	non	Level	1	REITs.

Debt	is	carried	at	outstanding	principal	balance,	less	any	unamortized	issuance	costs,	discount	or	premium.	Fair	value	is	based	on	quoted	market	prices	or	estimates using	discounted	cash	flow	analyses	based	on	current	borrowing	rates	for	similar	types	of	borrowing	arrangements.

The	following	tables	present	the	categorization	of	the	Company's	assets	and	liabilities	that	are	measured	at	fair	value	on	a	recurring	basis	at	December	31,	2018	and December	31,	2017	(in	millions):

|  | Balance	at	December	31,<br>2018 | Quoted	Prices	in<br>Active	Markets<br>for	Identical<br>Assets	(Level	1) | Significant<br>Other<br>Observable<br>Inputs	(Level	2) | Significant<br>Unobservable<br>Inputs<br>(Level	3) |
| :--- | :--- | :--- | :--- | :--- |
| Assets |  |  |  |  |
| Money\tmarket\tfunds\t(1) | $1,759 | $1,759 | $— | $— |
| Other\tinvestments |  |  |  |  |
| Government\tbonds | $1 | $— | $1 | $— |
| Equity\tinvestments | $2 | $— | $2 | $— |
| Derivatives\t(2) |  |  |  |  |
| Gross\tforeign\texchange\tcontracts | $21 | $— | $21 | $— |
| Liabilities |  |  |  |  |
| Derivatives\t(2) |  |  |  |  |
| Gross\tforeign\texchange\tcontracts | $12 | $— | $12 | $— |

(1) Included	within	Fiduciary	assets	or	Short-term	investments	in	the	Consolidated	Statements	of	Financial	Position,	depending	on	their	nature	and	initial	maturity.

(2) Refer	to	Note	15	"Derivatives	and	Hedging"	for	additional	information	regarding	the	Company's	derivatives	and	hedging	activity.

There	were	no	transfers	of	assets	or	liabilities	between	fair	value	hierarchy	levels	during	2018	or	2017.	The	Company	recognized	no	realized	or	unrealized	gains	or	losses in	the	Consolidated	Statements	of	Income	related	to	assets	and	liabilities	measured	at	fair	value	using	unobservable	inputs	in	2018,	2017,	or	2016.

The	fair	value	of	debt	is	classified	as	Level	2	of	the	fair	value	hierarchy.	The	following	table	provides	the	carrying	value	and	fair	value	for	the	Company's	term	debt	(in millions):

| As	of	December	31 | Carrying<br>Value | Fair<br>Value | Carrying<br>Value | Fair<br>Value |
| :--- | :--- | :--- | :--- | :--- |
| Current\tportion\tof\tlong-term\tdebt | $— | $— | $299 | $301 |
| Long-term\tdebt | $5,993 | $6,159 | $5,667 | $6,267 |

# 17.				Claims,	Lawsuits,	and	Other	Contingencies

# Legal

Aon	and	its	subsidiaries	are	subject	to	numerous	claims,	tax	assessments,	lawsuits	and	proceedings	that	arise	in	the	ordinary	course	of	business,	which	include	E&O claims.	The	damages	claimed	in	these	matters	are	or	may	be	substantial,	including,	in	many	instances,	claims	for	punitive,	treble	or	extraordinary	damages.	While	Aon maintains	meaningful	E&O	insurance	and	other	insurance	programs	to	provide	protection	against	certain	losses	that	arise	in	such	matters,	Aon	has	exhausted	or materially	depleted	its	coverage	under	some	of	the	policies	that	protect	the	Company	and,	consequently,	is	self-insured	or	materially	self-insured	for	some	claims. Accruals	for	these	exposures,	and	related	insurance	receivables,	when	applicable,	are	included	in	the	Consolidated	Statements	of	Financial	Position	and	have	been recognized	in	Other	general	expenses	in	the	Consolidated	Statements	of	Income	to	the	extent	that	losses	are	deemed	probable	and	are	reasonably	estimable.	These amounts	are	adjusted	from	time	to	time	as	developments	warrant.	Matters	that	are	not	probable	and	reasonably	estimable	are	not	accrued	for	in	the	financial	statements.

The	Company	has	included	in	the	current	matters	described	below	certain	matters	in	which	(1)	loss	is	probable,	(2)	loss	is	reasonably	possible;	that	is,	more	than	remote but	not	probable,	or	(3)	there	exists	the	reasonable	possibility	of	loss	greater	than	the	accrued	amount.	In	addition,	the	Company	may	from	time	to	time	disclose	matters for	which	the	probability	of	loss	could	be	remote	but	the	claim	amounts	associated	with	such	matters	are	potentially	significant.	The	reasonably	possible	range	of	loss	for the	matters	described	below,	in	excess	of	amounts	that	are	deemed	probable	and	estimable	and	therefore	already	accrued,	is	estimated	to	be	between	$0	and	$0.2	billion, exclusive	of	any	insurance	coverage.	These	estimates	are	based	on	currently	available	information.	As	available	information	changes,	the	matters	for	which	Aon	is	able to	estimate	may	change,	and	the	estimates	themselves	may	change.	In	addition,	many	estimates	involve	significant	judgment	and	uncertainty.	For	example,	at	the	time	of making	an	estimate,	Aon	may	only	have	limited	information	about	the	facts	underlying	the	claim,	and	predictions	and	assumptions	about	future	court	rulings	and outcomes	may	prove	to	be	inaccurate.	Although	management	at	present	believes	that	the	ultimate	outcome	of	all	matters	described	below,	individually	or	in	the aggregate,	will	not	have	a	material	adverse	effect	on	the	consolidated	financial	position	of

Aon,	legal	proceedings	are	subject	to	inherent	uncertainties	and	unfavorable	rulings	or	other	events.	Unfavorable	resolutions	could	include	substantial	monetary	or punitive	damages	imposed	on	Aon	or	its	subsidiaries.	If	unfavorable	outcomes	of	these	matters	were	to	occur,	future	results	of	operations	or	cash	flows	for	any	particular quarterly	or	annual	period	could	be	materially	adversely	affected.

# Current	Matters

A	pensions	consulting	and	administration	subsidiary	of	Aon	provided	advisory	services	to	the	Trustees	of	the	Gleeds	pension	fund	in	the	United	Kingdom	and,	on occasion,	to	the	relevant	employer	of	the	fund.	In	April	2014,	the	High	Court,	Chancery	Division,	London	found	that	certain	governing	documents	of	the	fund	that sought	to	alter	the	fund's	benefit	structure	and	that	had	been	drafted	by	Aon	were	procedurally	defective	and	therefore	invalid.		No	lawsuit	naming	Aon	as	a	party	was filed,	although	a	tolling	agreement	was	entered.		The	High	Court	decision	says	that	the	additional	liabilities	in	the	pension	fund	resulting	from	the	alleged	defect	in governing	documents	amount	to	approximately	£45	million	($57	million	at	December	31,	2018	exchange	rates).	In	December	2014,	the	Court	of	Appeal	granted	the employer	leave	to	appeal	the	High	Court	decision.	At	a	hearing	in	October	2016,	the	Court	of	Appeal	approved	a	settlement	of	the	pending	litigation.	On	October	31, 2016,	the	fund's	trustees	and	employer	sued	Aon	in	the	High	Court,	Chancery	Division,	London,	alleging	negligence	and	breach	of	duty	in	relation	to	the	governing documents.	The	proceedings	were	served	on	Aon	on	December	20,	2016.	The	claimants	seek	damages	of	approximately	£70	million	($88	million	at	December	31,	2018 exchange	rates).	In	February	2018,	the	claimants	instructed	new	lawyers	and	in	May	2018	added	their	previous	lawyers	as	defendants	to	the	Aon	lawsuit.	The	claimants allege	that	the	previous	lawyers	were	responsible	for	some	of	the	losses	sought	from	Aon	because	the	lawyers	gave	negligent	legal	advice	during	the	High	Court	and Court	of	Appeal	proceedings.	The	trial	of	this	matter	has	been	set	for	November	2019.	Aon	believes	that	it	has	meritorious	defenses	and	intends	to	vigorously	defend itself	against	this	claim.

On	June	29,	2015,	Lyttelton	Port	Company	Limited	("LPC")	sued	Aon	New	Zealand	in	the	Christchurch	Registry	of	the	High	Court	of	New	Zealand.		LPC	alleges, among	other	things,	that	Aon	was	negligent	and	in	breach	of	contract	in	arranging	LPC's	property	insurance	program	for	the	period	covering	June	30,	2010,	to	June	30, 2011.		LPC	contends	that	acts	and	omissions	by	Aon	caused	LPC	to	recover	less	than	it	otherwise	would	have	from	insurers	for	losses	suffered	in	the	2010	and	2011 Canterbury	earthquakes.		LPC	claims	damages	of	approximately	NZD	$184	million	($124	million	at	December	31,	2018	exchange	rates)	plus	interest	and	costs.		Aon believes	that	it	has	meritorious	defenses	and	intends	to	vigorously	defend	itself	against	these	claims.

On	October	3,	2017,	Christchurch	City	Council	("CCC")	invoked	arbitration	to	pursue	a	claim	that	it	asserts	against	Aon	New	Zealand.	Aon	provided	insurance	broking services	 to	CCC	 in	relation	 to	CCC's	2010-2011	material	damage	and	business	 interruption	program.	In	December	2015,	CCC	settled	 its	property	and	business interruption	claim	for	its	losses	arising	from	the	2010-2011	Canterbury	earthquakes	against	the	underwriter	of	its	material	damage	and	business	interruption	program and	the	reinsurers	of	that	underwriter.	CCC	contends	that	acts	and	omissions	by	Aon	caused	CCC	to	recover	less	in	that	settlement	than	it	otherwise	would	have.	CCC claims	damages	of	approximately	NZD	$528	million	($355	million	at	December	31,	2018	exchange	rates)	plus	interest	and	costs.	Aon	believes	that	it	has	meritorious defenses	and	intends	to	vigorously	defend	itself	against	these	claims.

A	retail	insurance	brokerage	subsidiary	of	Aon	was	sued	on	September	6,	2018	in	the	United	States	District	Court	for	the	Southern	District	of	New	York	by	a	client, Pilkington	North	America,	Inc.,	that	sustained	damage	from	a	tornado	to	its	Ottawa,	Illinois	property.	The	lawsuit	seeks	between	$45	million	 and	$85	million	in property	and	business	interruption	damages	from	either	its	insurer	or	Aon.	The	insurer	contends	that	insurance	proceeds	were	limited	to	$15	million	in	coverage	by	a windstorm	sub-limit	purportedly	contained	in	the	policy	procured	by	Aon	for	Pilkington.	The	insurer	therefore	has	tendered	$15	million	to	Pilkington	and	denied coverage	for	the	remainder	of	the	loss.	Pilkington	sued	the	insurer	and	Aon	seeking	full	coverage	for	the	loss	from	the	insurer	or,	in	the	alternative,	seeking	the	same damages	against	Aon	on	various	theories	of	professional	liability	if	the	court	finds	that	the	$15	million	sub-limit	applies	to	the	claim.	Aon	believes	it	has	meritorious defenses	and	intends	to	vigorously	defend	itself	against	these	claims.

In	April	2017,	the	FCA	announced	an	investigation	relating	to	suspected	competition	law	breaches	in	the	aviation	and	aerospace	broking	industry,	which,	for	Aon	in 2016,	represented	less	than	$100	million	in	global	revenue.	The	European	Commission	has	now	assumed	jurisdiction	over	the	investigation	in	place	of	the	FCA.	Other antitrust	agencies	outside	the	European	Union	are	also	conducting	formal	or	informal	investigations	regarding	these	matters.	Aon	intends	to	work	diligently	with	all antitrust	agencies	concerned	to	ensure	they	can	carry	out	their	work	as	efficiently	as	possible.	At	this	time,	in	light	of	the	uncertainties	and	many	variables	involved,	Aon cannot	estimate	the	ultimate	impact	on	our	company	from	these	investigations	or	any	related	private	litigation,	nor	any	damages,	penalties,	or	fines	related	to	them. There	can	be	no	assurance	that	the	ultimate	resolution	of	these	matters	will	not	have	a	material	adverse	effect	on	the	Company's	consolidated	financial	position,	results of	operations,	or	liquidity.

# Settled/Closed	Matters

	A	retail	insurance	brokerage	subsidiary	of	Aon	was	sued	on	September	14,	2010	in	the	Chancery	Court	for	Davidson	County,	Tennessee	Twentieth	Judicial	District,	at Nashville	by	a	client,	Opry	Mills	Mall	Limited	Partnership	("Opry	Mills"),	that	sustained	flood	damage	to	its	property	in	May	2010.	The	lawsuit	sought	$200	million	in coverage	from	numerous	insurers	with	whom	this	Aon	subsidiary	placed	the	client's	property	insurance	coverage.	The	insurers	contended	that	only	$50	million	in coverage	(which	had	already	been	paid)	was	available	for	the	loss	because	the	flood	event	occurred	on	property	in	a	high	hazard	flood	zone.	Opry	Mills	sought	full coverage	from	the	insurers	for	the	loss	and	sued	this	Aon	subsidiary	in	the	alternative	for	the	same	$150	million	difference	on	various	theories	of	professional	liability	if the	court	determined	 there	was	not	full	coverage.	In	addition,	Opry	Mills	sought	prejudgment	 interest,	attorneys'	fees	and	enhanced	damages	which	could	have substantially	increased	Aon's	exposure.	In	March	2015,	the	trial	court	granted	partial	summary	judgment	in	favor	of	plaintiffs	and	against	the	insurers,	holding	generally that	the	plaintiffs	are	entitled	to	$200	million	in	coverage	under	the	language	of	the	policies.	In	August	2015,	a	jury	returned	a	verdict	in	favor	of	Opry	Mills	and	against the	insurers	in	the	amount	of	$204	million.	On	January	26,	2018,	the	Tennessee	Court	of	Appeals	reversed	and	remanded,	reversing	summary	judgment	in	favor	of plaintiffs	and	concluding	that	coverage	is	limited	to	$50	million.	In	December	2018,	the	parties	reach	an	agreement	to	settle	this	case,	and	the	settlement	is	now concluded.	The	terms	of	this	settlement	did	not	have	a	significant	impact	on	Aon's	results	of	operations	or	financial	condition.

# Guarantees	and	Indemnifications

The	Company	provides	a	variety	of	guarantees	and	indemnifications	to	its	customers	and	others.	The	maximum	potential	amount	of	future	payments	represents	the notional	amounts	that	could	become	payable	under	the	guarantees	and	indemnifications	if	there	were	a	total	default	by	the	guaranteed	parties,	without	consideration	of possible	recoveries	under	recourse	provisions	or	other	methods.	These	amounts	may	bear	no	relationship	to	the	expected	future	payments,	if	any,	for	these	guarantees and	indemnifications.	Any	anticipated	amounts	payable	are	included	in	the	Company's	Consolidated	Financial	Statements,	and	are	recorded	at	fair	value.

The	Company	expects	that,	as	prudent	business	interests	dictate,	additional	guarantees	and	indemnifications	may	be	issued	from	time	to	time.

# Redomestication

In	connection	with	the	Redomestication,	the	Company	on	April	2,	2012	entered	into	various	agreements	pursuant	to	which	it	agreed	to	guarantee	the	obligations	of	its subsidiaries	arising	under	issued	and	outstanding	debt	securities.	Those	agreements	included	the	(1)	Amended	and	Restated	Indenture,	dated	as	of	April	2,	2012,	among Aon	Corporation,	Aon	plc,	and	The	Bank	of	New	York	Mellon	Trust	Company,	N.A.,	as	trustee	(the	"Trustee")	(amending	and	restating	the	Indenture,	dated	as	of September	10,	2010,	between	Aon	Corporation	and	the	Trustee),	(2)	Amended	and	Restated	Indenture,	dated	as	of	April	2,	2012,	among	Aon	Corporation,	Aon	plc	and the	Trustee	(amending	and	restating	the	Indenture,	dated	as	of	December	16,	2002,	between	Aon	Corporation	and	the	Trustee),	and	(3)	Amended	and	Restated	Indenture, dated	as	of	April	2,	2012,	among	Aon	Corporation,	Aon	plc	and	the	Trustee	(amending	and	restating	the	Indenture,	dated	as	of	January	13,	1997,	as	supplemented	by	the First	Supplemental	Indenture,	dated	as	of	January	13,	1997).

# Sale	of	the	Divested	Business

In	connection	with	the	sale	of	the	Divested	Business,	the	Company	guaranteed	future	operating	lease	commitments	related	to	certain	facilities	assumed	by	the	Buyer.	The Company	is	obligated	to	perform	under	the	guarantees	if	the	Divested	Business	defaults	on	such	leases	at	any	time	during	the	remainder	of	the	lease	agreements,	which expire	on	various	dates	through	2025.	As	of	December	31,	2018,	the	undiscounted	maximum	potential	future	payments	under	the	lease	guarantee	is	$85	million,	with	an estimated	fair	value	of	$17	million.	No	cash	payments	were	made	in	connection	to	the	lease	commitments	during	2018.

Additionally,	the	Company	is	subject	to	performance	guarantee	requirements	under	certain	client	arrangements	that	were	assumed	by	the	Buyer.		Should	the	Divested Business	fail	to	perform	as	required	by	the	terms	of	the	arrangements,	the	Company	would	be	required	to	fulfill	the	remaining	contract	terms,	which	expire	on	various dates	through	2023.		As	of	December	31,	2018,	the	undiscounted	maximum	potential	future	payments	under	the	performance	guarantees	were	$188	million,	with	an estimated	fair	value	of	$1	million.	No	cash	payments	were	made	in	connection	to	the	lease	commitments	during	2018.

# Letters	of	Credit

Aon	has	entered	into	a	number	of	arrangements	whereby	the	Company's	performance	on	certain	obligations	is	guaranteed	by	a	third	party	through	the	issuance	of	a	letter of	credit	("LOCs").	The	Company	had	total	LOCs	outstanding	of	approximately	$83	million	at	December	31,	2018,	compared	to	$96	million	at	December	31,	2017. These	letters	of	credit	cover	the	beneficiaries	related	to	certain	of	Aon's	U.S.	and	Canadian	non-qualified	pension	plan	schemes	and	secure	deductible	retentions	for Aon's	own	workers	compensation	program.	The	Company	has	also	obtained	LOCs	to	cover	contingent	payments	for	taxes	and	other	business	obligations	to	third	parties, and	other	guarantees	for	miscellaneous	purposes	at	its	international	subsidiaries.

# Premium	Payments

# 18.				Segment	Information

The	Company	operates	as	one	segment	that	includes	all	of	Aon's	continuing	operations,	which	as	a	global	professional	services	firm	provides	advice	and	solutions	to clients	focused	on	risk,	retirement,	and	health	through	five	revenue	lines	which	make	up	its	principal	products	and	services.	The	Chief	Operating	Decision	Maker	(the "CODM")	assesses	the	performance	of	the	Company	and	allocates	resources	based	on	one	segment:	Aon	United.

The	Company's	reportable	operating	segment	has	been	determined	using	a	management	approach,	which	is	consistent	with	the	basis	and	manner	in	which	Aon's	CODM uses	financial	information	for	the	purposes	of	allocating	resources	and	evaluating	performance.	The	CODM	assesses	performance	and	allocates	resources	based	on	total Aon	 results	 against	 its	 key	four	metrics,	 including	organic	revenue	growth,	expense	discipline,	and	collaborative	behaviors	 that	maximize	value	for	Aon	and	 its shareholders,	regardless	of	which	revenue	line	it	benefits.

As	Aon	operates	as	one	segment,	segment	profit	or	loss	is	consistent	with	consolidated	reporting	as	disclosed	on	the	Consolidated	Statements	of	Income.	Refer	to	Note	3 "Revenue	from	Contracts	with	Customers"	for	further	information	on	revenue	by	principal	service	line.

Consolidated	Non-current	assets	by	geographic	area	are	as	follows	(in	millions):

| Years	ended	December	31 | Total | United<br>States | Americas<br>other	than<br>U.S. | United<br>Kingdom | Europe,<br>Middle	East,<br>&amp;	Africa | Asia<br>Pacific |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 2018 | $588 | $288 | $44 | $58 | $101 | $97 |
| 2017 | $564 | $239 | $47 | $68 | $114 | $96 |

# 19.				Guarantee	of	Registered	Securities

As	described	in	Note	17	"Claims,	Lawsuits,	and	Other	Contingencies,"	in	connection	with	the	Redomestication,	Aon	plc	entered	into	various	agreements	pursuant	to which	it	agreed	to	guarantee	the	obligations	of	Aon	Corporation	arising	under	issued	and	outstanding	debt	securities,	including	the	5.00%	Notes	due	September	2020, the	8.205%	Notes	due	January	2027,	and	the	6.25%	Notes	due	September	2040	(collectively,	the	"Aon	Corp	Notes").	Additionally,	Aon	plc	has	agreed	to	guarantee	the obligations	of	Aon	Corporation	arising	under	the	4.50%	Senior	Notes	due	2028.	Aon	Corporation	is	a	100%	indirectly	owned	subsidiary	of	Aon	plc.	All	guarantees	of Aon	plc	are	full	and	unconditional.	There	are	no	other	subsidiaries	of	Aon	plc	that	are	guarantors	of	the	Aon	Corp	Notes.

In	addition,	Aon	Corporation	entered	into	an	agreement	pursuant	to	which	it	agreed	to	guarantee	the	obligations	of	Aon	plc	arising	under	the	4.25%	Notes	due	2042 exchanged	for	Aon	Corporation's	outstanding	8.205%	Notes	due	January	2027	and	has	also	agreed	to	guarantee	the	obligations	of	Aon	plc	arising	under	the	4.45% Notes	due	2043,	the	4.00%	Notes	due	November	2023,	the	2.875%	Notes	due	May	2026,	the	3.50%	Notes	due	June	2024,	the	4.60%	Notes	due	June	2044,	the	4.75% Notes	due	May	2045,	the	2.80%	Notes	due	March	2021,	and	the	3.875%	Notes	due	December	2025	(collectively,	the	"Aon	plc	Notes").	In	each	case,	the	guarantee	of Aon	Corporation	is	full	and	unconditional.	There	are	no	subsidiaries	of	Aon	plc,	other	than	Aon	Corporation,	that	are	guarantors	of	the	Aon	plc	Notes.	As	a	result	of	the existence	of	these	guarantees,	the	Company	has	elected	to	present	the	financial	information	set	forth	in	this	footnote	in	accordance	with	Rule	3-10	of	Regulation	S-X.

In	December	2018,	Aon	plc	obtained	direct	ownership	in	two	subsidiaries	that	were	previously	indirectly	owned	by	Aon	Corporation.	The	financial	results	of	both subsidiaries	are	included	in	the	Other	Non-Guarantor	Subsidiaries	column	of	the	Condensed	Consolidating	Financial	Statements.	The	Company	has	reflected	this transfer	on	the	Condensed	Consolidating	Statements	of	Income	and	Condensed	Consolidating	Statements	of	Comprehensive	Income	for	the	periods	ended	December	31, 2017	and	2016	and	the	Condensed	Consolidating	Statement	of	Financial	Position	for	the	period	ended	December	31,	2017.

The	following	tables	set	forth	Condensed	Consolidating	Statements	of	Income	and	Condensed	Consolidating	Statements	of	Comprehensive	Income	for	the	years	ended December	31,	2018,	2017,	and	2016,	Condensed	Consolidating	Statements	of	Financial	Position	as	of	December	31,	2018	and	December	31,	2017,	and	Condensed Consolidating	Statements	of	Cash	Flows	for	the	years	ended	December	31,	2018,	2017,	and	2016,	in	accordance	with	Rule	3-10	of	Regulation	S-X.	The	condensed consolidating	financial	information	includes	the	accounts	of	Aon	plc,	the	accounts	of	Aon	Corporation,	and	the	combined	accounts	of	the	non-guarantor	subsidiaries. The	condensed	consolidating	financial	statements	are	presented	in	all	periods	as	a	merger	under	common	control.	The	principal	consolidating	adjustments	are	to eliminate	the	investment	in	subsidiaries	and	intercompany	balances	and	transactions.

# Condensed	Consolidating	Statement	of	Income

| (millions) | Aon	plc | Aon	Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Revenue |  |  |  |  |  |
| Total\trevenue | $— | $— | $10,770 | $— | $10,770 |
| Expenses |  |  |  |  |  |
| Compensation\tand\tbenefits | 74 | (1) | 6,030 | — | 6,103 |
| Information\ttechnology | — | — | 484 | — | 484 |
| Premises | — | — | 370 | — | 370 |
| Depreciation\tof\tfixed\tassets | — | — | 176 | — | 176 |
| Amortization\tand\timpairment\tof\tintangible\tassets | — | — | 593 | — | 593 |
| Other\tgeneral\texpenses\t(income) | 4 | 64 | 1,432 | — | 1,500 |
| Total\toperating\texpenses | 78 | 63 | 9,085 | — | 9,226 |
| Operating\tincome\t(loss) | (78) | (63) | 1,685 | — | 1,544 |
| Interest\tincome | — | 58 | — | (53) | 5 |
| Interest\texpense | (203) | (101) | (27) | 53 | (278) |
| Intercompany\tinterest\tincome\t(expense) | 15 | (514) | 499 | — | — |
| Intercompany\tother\tincome\t(expense) | 97 | (399) | 302 | — | — |
| Other\tincome\t(expense) | 9 | (48) | 35 | (21) | (25) |
| Income\t(loss)\tfrom\tcontinuing\toperations\tbefore\tincome\ttaxes | (160) | (1,067) | 2,494 | (21) | 1,246 |
| Income\ttax\texpense\t(benefit) | (60) | (192) | 398 | — | 146 |
| Net\tincome\t(loss)\tfrom\tcontinuing\toperations | (100) | (875) | 2,096 | (21) | 1,100 |
| Net\tIncome\tfrom\tdiscontinued\toperations | — | — | 74 | — | 74 |
| Net\tincome\t(loss)\tbefore\tequity\tin\tearnings\tof\tsubsidiaries | (100) | (875) | 2,170 | (21) | 1,174 |
| Equity\tin\tearnings\tof\tsubsidiaries | 1,255 | 1,004 | 129 | (2,388) | — |
| Net\tincome | 1,155 | 129 | 2,299 | (2,409) | 1,174 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | — | — | 40 | — | 40 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $1,155 | $129 | $2,259 | $(2,409) | $1,134 |

| (millions) | Aon	plc | Aon	Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Revenue |  |  |  |  |  |
| Total\trevenue | $— | $— | $9,998 | $— | $9,998 |
| Expenses |  |  |  |  |  |
| Compensation\tand\tbenefits | 150 | 26 | 5,827 | — | 6,003 |
| Information\ttechnology | — | — | 419 | — | 419 |
| Premises | — | — | 348 | — | 348 |
| Depreciation\tof\tfixed\tassets | — | — | 187 | — | 187 |
| Amortization\tand\timpairment\tof\tintangible\tassets | — | — | 704 | — | 704 |
| Other\tgeneral\texpenses\t(income) | 12 | (6) | 1,266 | — | 1,272 |
| Total\toperating\texpenses | 162 | 20 | 8,751 | — | 8,933 |
| Operating\tincome\t(loss) | (162) | (20) | 1,247 | — | 1,065 |
| Interest\tincome | — | 52 | 4 | (29) | 27 |
| Interest\texpense | (202) | (94) | (15) | 29 | (282) |
| Intercompany\tinterest\tincome\t(expense) | 14 | (543) | 529 | — | — |
| Intercompany\tother\tincome\t(expense) | 247 | (411) | 164 | — | — |
| Other\tincome\t(expense) | (27) | 12 | (128) | 18 | (125) |
| Income\t(loss)\tfrom\tcontinuing\toperations\tbefore\tincome\ttaxes | (130) | (1,004) | 1,801 | 18 | 685 |
| Income\ttax\texpense\t(benefit) | (43) | (110) | 403 | — | 250 |
| Net\tincome\t(loss)\tfrom\tcontinuing\toperations | (87) | (894) | 1,398 | 18 | 435 |
| Net\tIncome\tfrom\tdiscontinued\toperations | — | — | 828 | — | 828 |
| Net\tincome\t(loss)\tbefore\tequity\tin\tearnings\tof\tsubsidiaries | (87) | (894) | 2,226 | 18 | 1,263 |
| Equity\tin\tearnings\tof\tsubsidiaries | 1,295 | 1,121 | 227 | (2,643) | — |
| Net\tincome | 1,208 | 227 | 2,453 | (2,625) | 1,263 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | — | — | 37 | — | 37 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $1,208 | $227 | $2,416 | $(2,625) | $1,226 |

| (millions) | Aon	plc | Aon	Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Revenue |  |  |  |  |  |
| Total\trevenue | $— | $— | $9,409 | $— | $9,409 |
| Expenses |  |  |  |  |  |
| Compensation\tand\tbenefits | 130 | 6 | 5,378 | — | 5,514 |
| Information\ttechnology | — | — | 386 | — | 386 |
| Premises | — | — | 343 | — | 343 |
| Depreciation\tof\tfixed\tassets | — | — | 162 | — | 162 |
| Amortization\tand\timpairment\tof\tintangible\tassets |  | — | 157 | — | 157 |
| Other\tgeneral\texpenses\t(income) | — | 2 | 1,034 | — | 1,036 |
| Total\toperating\texpenses | 130 | 8 | 7,460 | — | 7,598 |
| Operating\tincome\t(loss) | (130) | (8) | 1,949 | — | 1,811 |
| Interest\tincome | — | 16 | 22 | (29) | 9 |
| Interest\texpense | (196) | (101) | (14) | 29 | (282) |
| Intercompany\tinterest\tincome\t(expense) | 14 | (541) | 527 | — | — |
| Intercompany\tother\tincome\t(expense) | 274 | (361) | 87 | — | — |
| Other\tincome\t(expense) | 15 | (170) | 36 | (18) | (137) |
| Income\t(loss)\tfrom\tcontinuing\toperations\tbefore\tincome\ttaxes | (23) | (1,165) | 2,607 | (18) | 1,401 |
| Income\ttax\texpense\t(benefit) | (55) | (325) | 528 | — | 148 |
| Net\tincome\t(loss)\tfrom\tcontinuing\toperations | 32 | (840) | 2,079 | (18) | 1,253 |
| Net\tIncome\tfrom\tdiscontinued\toperations | — | — | 177 | — | 177 |
| Net\tincome\t(loss)\tbefore\tequity\tin\tearnings\tof\tsubsidiaries | 32 | (840) | 2,256 | (18) | 1,430 |
| Equity\tin\tearnings\tof\tsubsidiaries | 1,382 | 1,249 | 409 | (3,040) | — |
| Net\tincome | 1,414 | 409 | 2,665 | (3,058) | 1,430 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | — | — | 34 | — | 34 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $1,414 | $409 | $2,631 | $(3,058) | $1,396 |

# Condensed	Consolidating	Statement	of	Comprehensive	Income

| (millions) | Aon	plc | Aon	Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Net\tincome | $1,155 | $129 | $2,299 | $(2,409) | $1,174 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | — | — | 40 | — | 40 |
| Net\tincome\tattributable\tto\tAon\tshareholders | 1,155 | 129 | 2,259 | (2,409) | 1,134 |
| Other\tcomprehensive\tincome\t(loss),\tnet\tof\ttax: |  |  |  |  |  |
| Change\tin\tfair\tvalue\tof\tfinancial\tinstruments | — | — | 11 | — | 11 |
| Foreign\tcurrency\ttranslation\tadjustments | — | — | (465) | 21 | (444) |
| Postretirement\tbenefit\tobligation | — | (2) | 19 | — | 17 |
| Total\tother\tcomprehensive\tincome\t(loss) | — | (2) | (435) | 21 | (416) |
| Equity\tin\tother\tcomprehensive\tincome\t(loss)\tof\tsubsidiaries,\tnet\tof\ntax | (433) | (415) | (417) | 1,265 | — |
| Less:\tOther\tcomprehensive\tincome\t(loss)\tattributable\tto\nnoncontrolling\tinterests | — | — | (4) | — | (4) |
| Total\tother\tcomprehensive\tincome\t(loss)\tattributable\tto\tAon\nshareholders | (433) | (417) | (848) | 1,286 | (412) |
| Comprehensive\tincome\t(loss)\tattributable\tto\tAon\tshareholders | $722 | $(288) | $1,411 | $(1,123) | $722 |

| (millions) | Aon	plc | Aon	Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Net\tincome | $1,208 | $227 | $2,453 | $(2,625) | $1,263 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | — | — | 37 | — | 37 |
| Net\tincome\tattributable\tto\tAon\tshareholders | 1,208 | 227 | 2,416 | (2,625) | 1,226 |
| Other\tcomprehensive\tincome\t(loss),\tnet\tof\ttax: |  |  |  |  |  |
| Change\tin\tfair\tvalue\tof\tfinancial\tinstruments | — | 3 | 9 | — | 12 |
| Foreign\tcurrency\ttranslation\tadjustments | — | — | 408 | (18) | 390 |
| Postretirement\tbenefit\tobligation | — | (101) | 120 | — | 19 |
| Total\tother\tcomprehensive\tincome\t(loss) | — | (98) | 537 | (18) | 421 |
| Equity\tin\tother\tcomprehensive\tincome\t(loss)\tof\tsubsidiaries,\tnet\tof\ntax | 434 | 515 | 417 | (1,366) | — |
| Less:\tOther\tcomprehensive\tincome\t(loss)\tattributable\tto\nnoncontrolling\tinterests | — | — | 5 | — | 5 |
| Total\tother\tcomprehensive\tincome\t(loss)\tattributable\tto\tAon\nshareholders | 434 | 417 | 949 | (1,384) | 416 |
| Comprehensive\tincome\t(loss)\tattributable\tto\tAon\tshareholders | $1,642 | $644 | $3,365 | $(4,009) | $1,642 |

| (millions) | Aon	plc | Aon<br>Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Net\tincome | $1,414 | $409 | $2,665 | $(3,058) | $1,430 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | — | — | 34 | — | 34 |
| Net\tincome\tattributable\tto\tAon\tshareholders | 1,414 | 409 | 2,631 | (3,058) | 1,396 |
| Other\tcomprehensive\tincome\t(loss),\tnet\tof\ttax: |  |  |  |  |  |
| Change\tin\tfair\tvalue\tof\tfinancial\tinstruments | — | (1) | (11) | — | (12) |
| Foreign\tcurrency\ttranslation\tadjustments | (2) | 21 | (532) | 18 | (495) |
| Postretirement\tbenefit\tobligation | — | 68 | (52) | — | 16 |
| Total\tother\tcomprehensive\tincome\t(loss) | (2) | 88 | (595) | 18 | (491) |
| Equity\tin\tother\tcomprehensive\tincome\t(loss)\tof\tsubsidiaries,\tnet\tof\ntax | (505) | (547) | (459) | 1,511 | — |
| Less:\tOther\tcomprehensive\tincome\t(loss)\tattributable\tto\nnoncontrolling\tinterests | — | — | (2) | — | (2) |
| Total\tother\tcomprehensive\tincome\t(loss)\tattributable\tto\tAon\nshareholders | (507) | (459) | (1,052) | 1,529 | (489) |
| Comprehensive\tincome\t(loss)\tattributable\tto\tAon\tshareholders | $907 | $(50) | $1,579 | $(1,529) | $907 |

# Condensed	Consolidating	Statement	of	Financial	Position

| (millions) | Aon	plc | Aon<br>Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Assets |  |  |  |  |  |
| Current\tassets |  |  |  |  |  |
| Cash\tand\tcash\tequivalents | $— | $862 | $575 | $(781) | $656 |
| Short-term\tinvestments | — | 56 | 116 | — | 172 |
| Receivables,\tnet | — | — | 2,760 | — | 2,760 |
| Fiduciary\tassets | — | — | 10,166 | — | 10,166 |
| Intercompany\treceivables | 191 | 897 | 11,454 | (12,542) | — |
| Other\tcurrent\tassets | — | 16 | 602 | — | 618 |
| Total\tcurrent\tassets | 191 | 1,831 | 25,673 | (13,323) | 14,372 |
| Goodwill | — | — | 8,171 | — | 8,171 |
| Intangible\tassets,\tnet | — | — | 1,149 | — | 1,149 |
| Fixed\tassets,\tnet | — | — | 588 | — | 588 |
| Deferred\ttax\tassets | 94 | 467 | 144 | (144) | 561 |
| Intercompany\treceivables | 403 | 261 | 7,405 | (8,069) | — |
| Prepaid\tpension | — | 5 | 1,128 | — | 1,133 |
| Other\tnon-current\tassets | 1 | 30 | 417 | — | 448 |
| Investment\tin\tsubsidiary | 8,433 | 19,065 | (897) | (26,601) | — |
| Total\tassets | $9,122 | $21,659 | $43,778 | $(48,137) | $26,422 |
| Liabilities\tand\tequity |  |  |  |  |  |
| Liabilities |  |  |  |  |  |
| Current\tliabilities |  |  |  |  |  |
| Accounts\tpayable\tand\taccrued\tliabilities | $274 | $70 | $2,380 | $(781) | $1,943 |
| Short-term\tdebt\tand\tcurrent\tportion\tof\tlong-term\tdebt | 250 | — | 1 | — | 251 |
| Fiduciary\tliabilities | — | — | 10,166 | — | 10,166 |
| Intercompany\tpayables | 213 | 11,695 | 634 | (12,542) | — |
| Other\tcurrent\tliabilities | — | 69 | 867 | — | 936 |
| Total\tcurrent\tliabilities | 737 | 11,834 | 14,048 | (13,323) | 13,296 |
| Long-term\tdebt | 4,231 | 1,762 | — | — | 5,993 |
| Deferred\ttax\tliabilities | — | — | 325 | (144) | 181 |
| Pension,\tother\tpostretirement\tand\tother\tpost-employment\tliabilities | — | 1,275 | 361 | — | 1,636 |
|  | — | 7,570 | 499 | (8,069) | — |
| Intercompany\tpayables |  |  |  |  |  |
| Other\tnon-current\tliabilities | 3 | 115 | 979 | — | 1,097 |
| Total\tliabilities | 4,971 | 22,556 | 16,212 | (21,536) | 22,203 |
| Total\tAon\tshareholders'\tequity | 4,151 | (897) | 27,498 | (26,601) | 4,151 |
| Noncontrolling\tinterests | — | — | 68 | — | 68 |
| Total\tequity | 4,151 | (897) | 27,566 | (26,601) | 4,219 |
| Total\tliabilities\tand\tequity | $9,122 | $21,659 | $43,778 | $(48,137) | $26,422 |

| (millions) | Aon	plc | Aon<br>Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Assets |  |  |  |  |  |
| Current\tassets |  |  |  |  |  |
| Cash\tand\tcash\tequivalents | $1 | $2,524 | $793 | $(2,562) | $756 |
| Short-term\tinvestments | — | 355 | 174 | — | 529 |
| Receivables,\tnet | — | 2 | 2,476 | — | 2,478 |
| Fiduciary\tassets | — | — | 9,625 | — | 9,625 |
| Intercompany\treceivables | 165 | 1,046 | 10,824 | (12,035) | — |
| Other\tcurrent\tassets | 1 | 29 | 259 | — | 289 |
| Total\tcurrent\tassets | 167 | 3,956 | 24,151 | (14,597) | 13,677 |
| Goodwill | — | — | 8,358 | — | 8,358 |
| Intangible\tassets,\tnet | — | — | 1,733 | — | 1,733 |
| Fixed\tassets,\tnet | — | — | 564 | — | 564 |
| Deferred\ttax\tassets | 99 | 396 | 143 | (249) | 389 |
| Intercompany\treceivables | 414 | 261 | 8,232 | (8,907) | — |
| Prepaid\tpension | — | 6 | 1,054 | — | 1,060 |
| Other\tnon-current\tassets | 1 | 35 | 271 | — | 307 |
| Investment\tin\tsubsidiary | 8,884 | 17,799 | (91) | (26,592) | — |
| Total\tassets | $9,565 | $22,453 | $44,415 | $(50,345) | $26,088 |
| Liabilities\tand\tequity |  |  |  |  |  |
| Liabilities |  |  |  |  |  |
| Current\tliabilities |  |  |  |  |  |
| Accounts\tpayable\tand\taccrued\tliabilities | $574 | $36 | $3,913 | $(2,562) | $1,961 |
| Short-term\tdebt\tand\tcurrent\tportion\tof\tlong-term\tdebt | — | — | 299 | — | 299 |
| Fiduciary\tliabilities | — | — | 9,625 | — | 9,625 |
| Intercompany\tpayables | 130 | 11,149 | 756 | (12,035) | — |
| Other\tcurrent\tliabilities | 16 | 64 | 790 | — | 870 |
| Total\tcurrent\tliabilities | 720 | 11,249 | 15,383 | (14,597) | 12,755 |
| Long-term\tdebt | 4,251 | 1,415 | 1 | — | 5,667 |
| Deferred\ttax\tliabilities | — | — | 376 | (249) | 127 |
| Pension,\tother\tpostretirement\tand\tother\tpost-employment\tliabilities | — | 1,391 | 398 | — | 1,789 |
|  | — | 8,398 | 509 | (8,907) | — |
| Intercompany\tpayables |  |  |  |  |  |
| Other\tnon-current\tliabilities | 11 | 91 | 1,000 | — | 1,102 |
| Total\tliabilities | 4,982 | 22,544 | 17,667 | (23,753) | 21,440 |
| Total\tAon\tshareholders'\tequity | 4,583 | (91) | 26,683 | (26,592) | 4,583 |
| Noncontrolling\tinterests | — | — | 65 | — | 65 |
| Total\tequity | 4,583 | (91) | 26,748 | (26,592) | 4,648 |
| Total\tliabilities\tand\tequity | $9,565 | $22,453 | $44,415 | $(50,345) | $26,088 |

# Condensed	Consolidating	Statement	of	Cash	Flows

| (millions) | Aon	plc | Aon<br>Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Cash\tflows\tfrom\toperating\tactivities |  |  |  |  |  |
| Cash\tprovided\tby\t(used\tfor)\toperating\tactivities\t-\tcontinuing\noperations | $1,575 | $3 | $3,608 | $(3,500) | $1,686 |
| Cash\tprovided\tby\toperating\tactivities\t-\tdiscontinued\noperations | — | — | — | — | — |
| Cash\tprovided\tby\t(used\tfor)\toperating\tactivities | 1,575 | 3 | 3,608 | (3,500) | 1,686 |
| Cash\tflows\tfrom\tinvesting\tactivities |  |  |  |  |  |
| Proceeds\tfrom\tinvestments | — | 24 | 955 | (908) | 71 |
| Payments\tfor\tinvestments | (13) | (47) | (33) | 13 | (80) |
| Net\tpurchases\t(sales)\tof\tshort-term\tinvestments\t-\tnon-fiduciary | — | 299 | 49 | — | 348 |
| Acquisition\tof\tbusinesses,\tnet\tof\tcash\tacquired | — | — | (58) | — | (58) |
| Sale\tof\tbusinesses,\tnet\tof\tcash\tsold | — | — | (10) | — | (10) |
| Capital\texpenditures | — | — | (240) | — | (240) |
| Cash\tprovided\tby\t(used\tfor)\tinvesting\tactivities\t-\tcontinuing\noperations | (13) | 276 | 663 | (895) | 31 |
| Cash\tused\tfor\tinvesting\tactivities\t-\tdiscontinued\toperations | — | — | — | — | — |
| Cash\tprovided\tby\t(used\tfor)\tinvesting\tactivities | (13) | 276 | 663 | (895) | 31 |
| Cash\tflows\tfrom\tfinancing\tactivities |  |  |  |  |  |
| Share\trepurchase | (1,470) | — | — | — | (1,470) |
| Advances\tfrom\t(to)\taffiliates | 156 | (2,291) | (4,041) | 6,176 | — |
| Issuance\tof\tshares\tfor\temployee\tbenefit\tplans | (149) | — | — | — | (149) |
| Issuance\tof\tdebt | 1,723 | 4,028 | 3 | — | 5,754 |
| Repayment\tof\tdebt | (1,441) | (3,678) | (298) | — | (5,417) |
| Cash\tdividends\tto\tshareholders | (382) | — | — | — | (382) |
| Noncontrolling\tinterests\tand\tother\tfinancing\tactivities |  | — | (35) | — | (35) |
| Cash\tprovided\tby\t(used\tfor)\tfinancing\tactivities\t-\tcontinuing\noperations | (1,563) | (1,941) | (4,371) | 6,176 | (1,699) |
| Cash\tused\tfor\tfinancing\tactivities\t-\tdiscontinued\toperations | — | — | — | — | — |
| Cash\tprovided\tby\t(used\tfor)\tfinancing\tactivities | (1,563) | (1,941) | (4,371) | 6,176 | (1,699) |
| Effect\tof\texchange\trate\tchanges\ton\tcash\tand\tcash\tequivalents | — | — | (118) | — | (118) |
| Net\tincrease\t(decrease)\tin\tcash\tand\tcash\tequivalents | (1) | (1,662) | (218) | 1,781 | (100) |
| Cash\tand\tcash\tequivalents\tat\tbeginning\tof\tyear | 1 | 2,524 | 793 | (2,562) | 756 |
| Cash\tand\tcash\tequivalents\tat\tend\tof\tyear | $— | $862 | $575 | $(781) | $656 |

| (millions) | Aon	plc | Aon<br>Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Cash\tflows\tfrom\toperating\tactivities |  |  |  |  |  |
| Cash\tprovided\tby\t(used\tfor)\toperating\tactivities\t-\tcontinuing\noperations | $2,787 | $503 | $2,010 | $(4,631) | $669 |
| Cash\tprovided\tby\toperating\tactivities\t-\tdiscontinued\noperations | — | — | 65 | — | 65 |
| Cash\tprovided\tby\t(used\tfor)\toperating\tactivities | 2,787 | 503 | 2,075 | (4,631) | 734 |
| Cash\tflows\tfrom\tinvesting\tactivities |  |  |  |  |  |
| Proceeds\tfrom\tinvestments | 224 | 587 | 582 | (1,325) | 68 |
| Payments\tfor\tinvestments | (261) | (29) | (576) | 802 | (64) |
| Net\tpurchases\t(sales)\tof\tshort-term\tinvestments\t-\tnon-fiduciary | — | (215) | (17) | — | (232) |
| Acquisition\tof\tbusinesses,\tnet\tof\tcash\tacquired | — | — | (1,029) | — | (1,029) |
| Sale\tof\tbusinesses,\tnet\tof\tcash\tsold | — | — | 4,246 | — | 4,246 |
| Capital\texpenditures | — | — | (183) | — | (183) |
| Cash\tprovided\tby\t(used\tfor)\tinvesting\tactivities\t-\tcontinuing\noperations | (37) | 343 | 3,023 | (523) | 2,806 |
| Cash\tused\tfor\tinvesting\tactivities\t-\tdiscontinued\toperations | — | — | (19) | — | (19) |
| Cash\tprovided\tby\t(used\tfor)\tinvesting\tactivities | (37) | 343 | 3,004 | (523) | 2,787 |
| Cash\tflows\tfrom\tfinancing\tactivities |  |  |  |  |  |
| Share\trepurchase | (2,399) | — | — | — | (2,399) |
| Advances\tfrom\t(to)\taffiliates | 426 | 95 | (4,975) | 4,454 | — |
| Issuance\tof\tshares\tfor\temployee\tbenefit\tplans | (121) | — | — | — | (121) |
| Issuance\tof\tdebt | 544 | 1,100 | 10 | — | 1,654 |
| Repayment\tof\tdebt | (835) | (1,150) | (14) | — | (1,999) |
| Cash\tdividends\tto\tshareholders | (364) | — | — | — | (364) |
| Noncontrolling\tinterests\tand\tother\tfinancing\tactivities | — | — | (36) | — | (36) |
| Cash\tprovided\tby\t(used\tfor)\tfinancing\tactivities\t-\tcontinuing\noperations | (2,749) | 45 | (5,015) | 4,454 | (3,265) |
| Cash\tused\tfor\tfinancing\tactivities\t-\tdiscontinued\toperations | — | — | — | — | — |
| Cash\tprovided\tby\t(used\tfor)\tfinancing\tactivities | (2,749) | 45 | (5,015) | 4,454 | (3,265) |
| Effect\tof\texchange\trate\tchanges\ton\tcash\tand\tcash\tequivalents | — | — | 69 | — | 69 |
| Net\tincrease\t(decrease)\tin\tcash\tand\tcash\tequivalents | 1 | 891 | 133 | (700) | 325 |
| Cash\tand\tcash\tequivalents\tat\tbeginning\tof\tyear\t(1) | — | 1,633 | 660 | (1,862) | 431 |
| Cash\tand\tcash\tequivalents\tat\tend\tof\tyear\t(2) | $1 | $2,524 | $793 | $(2,562) | $756 |

(1) Includes	$5	million	of	discontinued	operations	at	December	31,	2016.

(2) Includes	$0	million	of	discontinued	operations	at	December	31,	2017

| (millions) | Aon	plc | Aon<br>Corporation | Non-Guarantor<br>Subsidiaries | Consolidating<br>Adjustments | Consolidated |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Cash\tflows\tfrom\toperating\tactivities |  |  |  |  |  |
| Cash\tprovided\tby\t(used\tfor)\toperating\tactivities\t-\tcontinuing\noperations | $2,705 | $(536) | $2,768 | $(3,108) | $1,829 |
| Cash\tprovided\tby\toperating\tactivities\t-\tdiscontinued\noperations | — | — | 497 | — | 497 |
| Cash\tprovided\tby\t(used\tfor)\toperating\tactivities | 2,705 | (536) | 3,265 | (3,108) | 2,326 |
| Cash\tflows\tfrom\tinvesting\tactivities |  |  |  |  |  |
| Proceeds\tfrom\tinvestments | — | 316 | 15 | (288) | 43 |
| Payments\tfor\tinvestments | — | (35) | (29) | — | (64) |
| Net\tpurchases\t(sales)\tof\tshort-term\tinvestments\t-\tnon-fiduciary | — | 70 | (9) | — | 61 |
| Acquisition\tof\tbusinesses,\tnet\tof\tcash\tacquired | — | (335) | (608) | 64 | (879) |
| Sale\tof\tbusinesses,\tnet\tof\tcash\tsold | — | — | 171 | (64) | 107 |
| Capital\texpenditures | — | — | (156) | — | (156) |
| Cash\tprovided\tby\t(used\tfor)\tinvesting\tactivities\t-\tcontinuing\noperations | — | 16 | (616) | (288) | (888) |
| Cash\tused\tfor\tinvesting\tactivities\t-\tdiscontinued\toperations | — | — | (66) | — | (66) |
| Cash\tprovided\tby\t(used\tfor)\tinvesting\tactivities | — | 16 | (682) | (288) | (954) |
| Cash\tflows\tfrom\tfinancing\tactivities |  |  |  |  |  |
| Share\trepurchase | (1,257) | — | — | — | (1,257) |
| Advances\tfrom\t(to)\taffiliates | (2,008) | 570 | (3,037) | 4,475 | — |
| Issuance\tof\tshares\tfor\temployee\tbenefit\tplans | (129) | — | — | — | (129) |
| Issuance\tof\tdebt | 1,879 | 1,588 | — | — | 3,467 |
| Repayment\tof\tdebt | (845) | (2,088) | (12) | — | (2,945) |
| Cash\tdividends\tto\tshareholders | (345) | — | — | — | (345) |
| Noncontrolling\tinterests\tand\tother\tfinancing\tactivities | — | — | (77) | — | (77) |
| Cash\tprovided\tby\t(used\tfor)\tfinancing\tactivities\t-\tcontinuing\noperations | (2,705) | 70 | (3,126) | 4,475 | (1,286) |
| Cash\tused\tfor\tfinancing\tactivities\t-\tdiscontinued\toperations | — | — | — | — | — |
| Cash\tprovided\tby\t(used\tfor)\tfinancing\tactivities | (2,705) | 70 | (3,126) | 4,475 | (1,286) |
| Effect\tof\texchange\trate\tchanges\ton\tcash\tand\tcash\tequivalents | — | — | (39) | — | (39) |
| Net\tincrease\t(decrease)\tin\tcash\tand\tcash\tequivalents | — | (450) | (582) | 1,079 | 47 |
| Cash\tand\tcash\tequivalents\tat\tbeginning\tof\tyear\t(1) | — | 2,083 | 1,242 | (2,941) | 384 |
| Cash\tand\tcash\tequivalents\tat\tend\tof\tyear\t(2) | $— | $1,633 | $660 | $(1,862) | $431 |

# 20.				Quarterly	Financial	Data	(Unaudited)

Selected	quarterly	financial	data	for	the	years	ended	December	31,	2018	and	2017	are	as	follows	(in	millions,	except	per	share	data):

|  | 1Q | 2Q | 3Q | 4Q | 2018 |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Income\tStatement\tData |  |  |  |  |  |
| Total\trevenue | $3,090 | $2,561 | $2,349 | $2,770 | $10,770 |
| Operating\tincome | 799 | (16) | 262 | 499 | 1,544 |
| Net\tincome\tfrom\tcontinuing\toperations | 604 | 57 | 155 | 284 | 1,100 |
| Income\tfrom\tdiscontinued\toperations,\tnet\tof\ttax | 6 | 1 | (2) | 69 | 74 |
| Net\tincome | 610 | 58 | 153 | 353 | 1,174 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | 16 | 10 | 6 | 8 | 40 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $594 | $48 | $147 | $345 | $1,134 |
| Per\tShare\tData |  |  |  |  |  |
| Basic\tnet\tincome\tper\tshare\tattributable\tto\tAon\tshareholders |  |  |  |  |  |
| Continuing\toperations | $2.37 | $0.19 | $0.61 | $1.14 | $4.32 |
| Discontinued\toperations | 0.02 | 0.01 | (0.01) | 0.28 | 0.30 |
| Net\tincome | $2.39 | $0.20 | $0.60 | $1.42 | $4.62 |
| Diluted\tnet\tincome\tper\tshare\tattributable\tto\tAon\tshareholders |  |  |  |  |  |
| Continuing\toperations | $2.35 | $0.19 | $0.61 | $1.13 | $4.29 |
| Discontinued\toperations | 0.02 | — | (0.01) | 0.28 | 0.30 |
| Net\tincome | $2.37 | $0.19 | $0.60 | $1.41 | $4.59 |

|  | 1Q | 2Q | 3Q | 4Q | 2017 |
| :--- | :--- | :--- | :--- | :--- | :--- |
| Income\tStatement\tData |  |  |  |  |  |
| Total\trevenue | $2,381 | $2,368 | $2,340 | $2,909 | $9,998 |
| Operating\tincome | 335 | (127) | 256 | 601 | 1,065 |
| Net\tincome\tfrom\tcontinuing\toperations | 265 | (43) | 196 | 17 | 435 |
| Income\tfrom\tdiscontinued\toperations,\tnet\tof\ttax | 40 | 821 | (4) | (29) | 828 |
| Net\tincome | 305 | 778 | 192 | (12) | 1,263 |
| Less:\tNet\tincome\tattributable\tto\tnoncontrolling\tinterests | 14 | 9 | 7 | 7 | 37 |
| Net\tincome\tattributable\tto\tAon\tshareholders | $291 | $769 | $185 | $(19) | $1,226 |
| Per\tShare\tData |  |  |  |  |  |
| Basic\tnet\tincome\tper\tshare\tattributable\tto\tAon\tshareholders |  |  |  |  |  |
| Continuing\toperations | $0.95 | $(0.20) | $0.74 | $0.04 | $1.54 |
| Discontinued\toperations | 0.15 | 3.13 | (0.02) | (0.12) | 3.20 |
| Net\tincome | $1.10 | $2.93 | $0.72 | $(0.08) | $4.74 |
| Diluted\tnet\tincome\tper\tshare\tattributable\tto\tAon\tshareholders |  |  |  |  |  |
| Continuing\toperations | $0.94 | $(0.20) | $0.73 | $0.04 | $1.53 |
| Discontinued\toperations | 0.15 | 3.13 | (0.01) | (0.11) | 3.17 |
| Net\tincome | $1.09 | $2.93 | $0.72 | $(0.07) | $4.70 |

# Item	9.				Changes	in	and	Disagreements	with	Accountants	on	Accounting	and	Financial	Disclosure

# Item	9A.				Controls	and	Procedures

# Evaluation	of	Disclosure	Controls	and	Procedures

We	have	conducted	an	evaluation	of	the	effectiveness	of	the	design	and	operation	of	our	disclosure	controls	and	procedures,	as	defined	in	Rules	13a-15(e)	and	15d- 15(e)	under	the	Securities	Exchange	Act	of	1934,	as	amended	(the	"Exchange	Act")	as	of	the	end	of	the	period	covered	by	this	annual	report	of	December	31,	2018. Based	on	this	evaluation,	our	chief	executive	officer	and	chief	financial	officer	concluded	as	of	December	31,	2018	that	our	disclosure	controls	and	procedures	were effective	 such	 that	 the	 information	 relating	 to	Aon,	 including	 our	 consolidated	 subsidiaries,	 required	 to	 be	 disclosed	 in	 our	 SEC	 reports	 is	 recorded,	 processed, summarized	and	reported	within	the	time	periods	specified	in	SEC	rules	and	forms,	and	is	accumulated	and	communicated	to	Aon's	management,	including	our	chief executive	officer	and	chief	financial	officer,	as	appropriate	to	allow	timely	decisions	regarding	required	disclosure.

# Management's	Report	on	Internal	Control	Over	Financial	Reporting

Management	of	Aon	plc	is	responsible	for	establishing	and	maintaining	adequate	internal	control	over	financial	reporting	as	defined	in	Rules	13a-15(f)	and	15d- 15(f)	under	the	Exchange	Act.	The	Company's	internal	control	over	financial	reporting	is	designed	to	provide	reasonable	assurance	regarding	the	reliability	of	financial reporting	and	the	preparation	of	financial	statements	for	external	purposes	in	accordance	with	U.S.	generally	accepted	accounting	principles.	Because	of	its	inherent limitations,	internal	control	over	financial	reporting	may	not	prevent	or	detect	misstatements.	Also,	projections	of	any	evaluation	of	effectiveness	to	future	periods	are subject	to	the	risk	that	controls	may	become	inadequate	because	of	changes	in	conditions,	or	that	the	degree	of	compliance	with	the	policies	or	procedures	may deteriorate.

Under	the	supervision	and	with	the	participation	of	our	senior	management,	including	our	Chief	Executive	Officer	and	Chief	Financial	Officer,	we	assessed	the effectiveness	of	our	internal	control	over	financial	reporting	as	of	December	31,	2018.	In	making	this	assessment,	we	used	the	criteria	set	forth	by	the	Committee	of Sponsoring	Organizations	of	 the	Treadway	Commission	(COSO)	 in the	Internal	 Control	 — Integrated	 Framework	(2013	Framework).	Based	on	 this	assessment, management	has	concluded	our	internal	control	over	financial	reporting	is	effective	as	of	December	31,	2018.

The	effectiveness	of	our	internal	control	over	financial	reporting	as	of	December	31,	2018	has	been	audited	by	Ernst	&	Young,	LLP,	the	Company's	independent registered	public	accounting	firm,	as	stated	 in	 their	report	 titled	 "Report	 of	 Independent	 Registered	 Public	Accounting	 Firm	 on	 Internal	 Control	 Over	 Financial Reporting."

# Changes	in	Internal	Control	Over	Financial	Reporting

No	changes	in	Aon's	internal	control	over	financial	reporting	(as	defined	in	Rule	13a-15(f)	under	the	Exchange	Act)	occurred	during	2018	that	have	materially affected,	or	that	are	reasonably	likely	to	materially	affect,	Aon's	internal	control	over	financial	reporting.

# Opinion	on	Internal	Control	over	Financial	Reporting

We	 have	 audited	Aon	 plc's	 internal	 control	 over	 financial	 reporting	 as	 of	 December	 31,	 2018,	 based	 on	 criteria	 established	 in	 Internal	 Control-Integrated Framework	issued	by	the	Committee	of	Sponsoring	Organizations	of	the	Treadway	Commission	(2013	Framework),	(the	COSO	criteria).	In	our	opinion,	Aon	plc	(the Company)	maintained,	in	all	material	respects,	effective	internal	control	over	financial	reporting	as	of	December	31,	2018,	based	on	the	COSO	criteria.

We	also	have	audited,	in	accordance	with	the	standards	of	the	Public	Company	Accounting	Oversight	Board	(United	States)	(PCAOB),	the	consolidated	statement of	financial	position	of	the	Company	as	of	December	31,	2018	and	2017,	and	the	related	consolidated	statements	of	income,	comprehensive	income,	shareholders' equity	and	cash	flows	for	each	of	the	three	years	in	the	period	ended	December	31,	2018,	and	the	related	notes	and	our	report	dated	February	19,	2019	expressed	an unqualified	opinion	thereon.

The	Company's	management	is	responsible	for	maintaining	effective	internal	control	over	financial	reporting	and	for	its	assessment	of	the	effectiveness	of	internal control	over	financial	reporting	included	in	the	accompanying	Management's	Report	on	Internal	Control	Over	Financial	Reporting.	Our	responsibility	is	to	express	an opinion	on	the	Company's	internal	control	over	financial	reporting	based	on	our	audit.	We	are	a	public	accounting	firm	registered	with	the	PCAOB	and	are	required	to be	independent	with	respect	to	the	Company	in	accordance	with	the	U.S.	federal	securities	laws	and	the	applicable	rules	and	regulations	of	the	Securities	and	Exchange Commission	and	the	PCAOB.

We	conducted	our	audit	in	accordance	with	the	standards	of	the	PCAOB.	Those	standards	require	that	we	plan	and	perform	the	audit	to	obtain	reasonable	assurance about	whether	effective	internal	control	over	financial	reporting	was	maintained	in	all	material	respects.

Our	audit	included	obtaining	an	understanding	of	internal	control	over	financial	reporting,	assessing	the	risk	that	a	material	weakness	exists,	testing	and	evaluating the	 design	 and	 operating	 effectiveness	 of	 internal	 control	 based	 on	 the	 assessed	 risk,	 and	 performing	 such	 other	 procedures	 as	 we	 considered	 necessary	 in	 the circumstances.	We	believe	that	our	audit	provides	a	reasonable	basis	for	our	opinion.

# Definition	and	Limitations	of	Internal	Control	Over	Financial	Reporting

A	company's	internal	control	over	financial	reporting	is	a	process	designed	to	provide	reasonable	assurance	regarding	the	reliability	of	financial	reporting	and	the preparation	of	financial	statements	for	external	purposes	in	accordance	with	generally	accepted	accounting	principles.	A	company's	internal	control	over	financial reporting	includes	those	policies	and	procedures	that	(1)	pertain	to	the	maintenance	of	records	that,	in	reasonable	detail,	accurately	and	fairly	reflect	the	transactions	and dispositions	of	the	assets	of	the	company;	(2)	provide	reasonable	assurance	that	transactions	are	recorded	as	necessary	to	permit	preparation	of	financial	statements	in accordance	with	generally	accepted	accounting	principles,	and	that	receipts	and	expenditures	of	the	company	are	being	made	only	in	accordance	with	authorizations	of management	 and	 directors	 of	 the	 company;	 and	 (3)	 provide	 reasonable	 assurance	 regarding	 prevention	 or	 timely	 detection	 of	 unauthorized	 acquisition,	 use,	 or disposition	of	the	company's	assets	that	could	have	a	material	effect	on	the	financial	statements.

Because	of	 its	 inherent	 limitations,	 internal	control	over	financial	reporting	may	not	prevent	or	detect	misstatements.	Also,	projections	of	any	evaluation	of effectiveness	to	future	periods	are	subject	to	the	risk	that	controls	may	become	inadequate	because	of	changes	in	conditions,	or	that	the	degree	of	compliance	with	the policies	or	procedures	may	deteriorate.

Information	relating	to	Aon's	directors	is	set	forth	under	the	heading	"Proposal	1	—	Resolutions	Regarding	the	Election	of	Directors"	in	our	Proxy	Statement	for	the 2019	Annual	General	Meeting	of	Shareholders	to	be	held	on	June	21,	2019	(the	"Proxy	Statement")	and	is	incorporated	herein	by	reference.	Information	relating	to Aon's	executive	officers	is	set	forth	in	Part	I	of	this	report	and	is	incorporated	herein	by	reference.	Information	relating	to	compliance	with	Section	16(a)	of	the Exchange	Act	 is	set	forth	under	 the	heading	"Section	16(a)	Beneficial	Ownership	Reporting	Compliance"	 in	 the	Proxy	Statement	and	 is	 incorporated	herein	by reference.	The	remaining	information	required	by	this	item	is	set	forth	under	the	headings	"Corporate	Governance"	and	"Board	of	Directors	and	Committees"	in	the Proxy	Statement,	and	all	such	information	is	incorporated	herein	by	reference.

We	have	adopted	a	code	of	ethics	that	applies	to	the	Company's	directors,	officers,	and	employees,	including	the	Chief	Executive	Officer,	Chief	Financial	Officer, Controller,	and	Chief	Accounting	Officer	and	other	persons	performing	similar	functions.	The	text	of	our	code	of	ethics,	which	we	call	our	Code	of	Business	Conduct,	is available	on	our	website	as	disclosed	in	Part	1	of	this	report.	We	will	provide	a	copy	of	the	code	of	ethics	without	charge	upon	request	to	the	Company	Secretary,	Aon plc,	122	Leadenhall	Street,	London	EC3V	4AN,	United	Kingdom.	We	will	disclose	on	our	website	any	amendment	to	or	waiver	from	our	code	of	ethics	on	behalf	of any	of	our	executive	officers	or	directors.

Information	relating	to	director	and	executive	officer	compensation	is	set	forth	under	the	headings	"Compensation	Committee	Report,"	"Compensation	Discussion and	Analysis,"	and	"Executive	Compensation"	in	the	Proxy	Statement,	and	all	such	information	is	incorporated	herein	by	reference.

The	material	incorporated	herein	by	reference	to	the	information	set	forth	under	the	heading	"Compensation	Committee	Report"	in	the	Proxy	Statement	shall	be deemed	furnished,	and	not	filed,	in	this	Form	10-K	and	shall	not	be	deemed	incorporated	by	reference	into	any	filing	under	the	Securities	Act	of	1933,	as	amended,	or the	Exchange	Act	as	a	result	of	this	furnishing,	except	to	the	extent	that	it	is	specifically	incorporated	by	reference	by	Aon.

Information	relating	to	compensation	committee	interlocks	and	insider	participation	is	set	forth	under	the	heading	"Compensation	Discussion	and	Analysis	- Compensation	Committee	Interlocks	and	Insider	Participation"	in	the	Proxy	Statement	and	is	incorporated	herein	by	reference.

# Item	12.				Security	Ownership	of	Certain	Beneficial	Owners	and	Management	and	Related	Stockholder	Matters

Information	relating	to	equity	compensation	plans	and	the	security	ownership	of	certain	beneficial	owners	and	management	of	Aon	plc's	ordinary	shares	is	set	forth under	the	headings	"Equity	Compensation	Plan	Information,"	"Principal	Holders	of	Voting	Securities,"	and	"Security	Ownership	of	Directors	and	Executive	Officers"	in the	Proxy	Statement,	and	all	such	information	is	incorporated	herein	by	reference.

# Item	13.				Certain	Relationships	and	Related	Transactions,	and	Director	Independence

Information	required	by	this	Item	is	included	under	the	headings	"Corporate	Governance	—	Director	Independence"	and	"Certain	Relationships	and	Related Transactions"	in	the	Proxy	Statement	and	is	incorporated	herein	by	reference.

# Item	14.				Principal	Accountant	Fees	and	Services

Information	required	by	this	Item	is	included	under	the	heading	"Auditor	Fees"	in	the	Proxy	Statement	and	is	incorporated	herein	by	reference.

(a) (1)	and	(2).	The	following	documents	have	been	included	in	Part	II,	Item	8.

Report	of	Ernst	&	Young	LLP,	Independent	Registered	Public	Accounting	Firm,	on	Financial	Statements

Consolidated	Statements	of	Financial	Position	—	As	of	December	31,	2017	and	2016

Consolidated	Statements	of	Comprehensive	Income	—	Years	Ended	December	31,	2017,	2016	and	2015

Consolidated	Statements	of	Shareholders'	Equity	—	Years	Ended	December	31,	2017,	2016	and	2015

The	following	document	has	been	included	in	Part	II,	Item	9.

Report	of	Ernst	&	Young	LLP,	Independent	Registered	Public	Accounting	Firm,	on	Internal	Control	over	Financial	Reporting

All	schedules	for	the	Registrant	and	consolidated	subsidiaries	have	been	omitted	because	the	required	information	is	not	present	in	amounts	sufficient	to	require submission	of	the	schedules	or	because	the	information	required	is	included	in	the	respective	financial	statements	or	notes	thereto.

# (a)(3).	List	of	Exhibits	(numbered	in	accordance	with	Item	601	of	Regulation	S-K)

# Plan	of	Acquisition,	Reorganization,	Arrangement,	Liquidation	or	Succession.

2.1* Agreement	and	Plan	of	Merger	and	Reorganization	by	and	among	Aon	Corporation	and	Market	Mergeco	Inc.	dated	January	12,	2012	— incorporated	by	reference	to	Annex	A	of	the	Registration	Statement	on	Form	S-4/A	(File	No.	333-178991)	filed	by	Aon	Global	Limited	on February	6,	2012.

# Articles	of	Association.

3.1* Articles	of	Association	of	Aon	plc	—	incorporated	by	reference	to	Exhibit	3.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	April	2,	2012.

# Instruments	Defining	the	Rights	of	Security	Holders,	Including	Indentures.

4.1* Amended	and	Restated	Indenture,	dated	as	of	April	2,	2012,	among	Aon	Corporation,	Aon	plc	and	The	Bank	of	New	York	Mellon	Trust Company,	N.A.	(amending	and	restating	the	Indenture,	dated	as	of	January	13,	1997,	as	supplemented	by	the	First	Supplemental	Indenture, dated	as	of	January	13,	1997)	—	incorporated	by	reference	to	Exhibit	4.3	to	Aon's	Current	Report	on	Form	8-K	filed	on	April	2,	2012.

4.2* Capital	Securities	Guarantee	Agreement	dated	as	of	January	13,	1997	between	Aon	and	The	Bank	of	New	York,	as	Guarantee	Trustee	— incorporated	by	reference	to	Exhibit	4.8	to	Aon's	Registration	Statement	on	Form	S-4	(File	No.	333-21237)	filed	on	February	6,	1997.

4.3* Capital	Securities	Exchange	and	Registration	Rights	Agreement	dated	as	of	January	13,	1997	among	Aon,	Aon	Capital	A,	Morgan	Stanley	& Co.	Incorporated	and	Goldman,	Sachs	&	Co.	—	incorporated	by	reference	to	Exhibit	4.10	to	Aon's	Registration	Statement	on	Form	S-4	(File No.	333-21237)	filed	on	February	6,	1997.

4.4* Debenture	Exchange	and	Registration	Rights	Agreement	dated	as	of	January	13,	1997	among	Aon,	Aon	Capital	A,	Morgan	Stanley	&	Co. Incorporated	and	Goldman,	Sachs	&	Co.	—	incorporated	by	reference	to	Exhibit	4.11	to	Aon's	Registration	Statement	on	Form	S-4	(File No.	333-21237)	filed	on	February	6,	1997.

4.5* Guarantee	Exchange	and	Registration	Rights	Agreement	dated	as	of	January	13,	1997	among	Aon,	Aon	Capital	A,	Morgan	Stanley	&	Co. Incorporated	and	Goldman,	Sachs	&	Co.	—	incorporated	by	reference	to	Exhibit	4.12	to	Aon's	Registration	Statement	on	Form	S-4	(File No.	333-21237)	filed	on	February	6,	1997.

4.6* Amended	and	Restated	Indenture,	dated	as	of	April	2,	2012,	among	Aon	Corporation,	Aon	plc	and	The	Bank	of	New	York	Mellon	Trust Company,	N.A.,	as	trustee	(amending	and	restating	the	Indenture,	dated	as	of	September	10,	2010,	between	Aon	Corporation	and	The	Bank	of New	York	Mellon	Trust	Company,	N.A.)	—	incorporated	by	reference	to	Exhibit	4.2	to	Aon's	Current	Report	on	Form	8-K	filed	on	April	2, 2012.

4.9* Indenture	dated	as	of	March	8,	2011,	among	Aon	Finance	N.S.	1,	ULC,	Aon	Corporation	and	Computershare	Trust	Company	of	Canada.	— incorporated	by	reference	to	Exhibit	4.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	March	8,	2011.

4.10* First	Supplemental	Indenture,	dated	as	of	April	2,	2012,	among	Aon	Finance	N.S.	1,	ULC,	Aon	Corporation,	as	guarantor,	Aon	plc,	as guarantor,	and	Computershare	Trust	Company	of	Canada,	as	trustee	(supplementing	the	Indenture	dated	as	of	March	8,	2011	among	Aon Finance	N.S.1,	ULC,	Aon	Corporation,	as	guarantor,	and	Computershare	Trust	Company	of	Canada,	as	trustee)	—	incorporated	by	reference	to Exhibit	4.2	to	Aon's	Current	Report	on	Form	8-K	filed	on	April	2,	2012.

4.11* Indenture,	dated	as	of	December	12,	2012	by	and	among	Aon	plc,	Aon	Corporation,	The	Bank	of	New	York	Mellon	Trust	Company,	N.A.	— incorporated	by	reference	to	Exhibit	4.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	December	13,	2012.

4.13* Indenture,	dated	as	of	May	24,	2013,	among	Aon,	Aon	Corporation	and	The	Bank	of	New	York	Mellon	Trust	Company,	National	Association, as	trustee	(including	the	Guarantee)	—	incorporated	by	reference	to	Exhibit	4.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	May	24,	2013.

4.18*	 Amended	and	Restated	Indenture,	dated	as	of	May	20,	2015,	among	Aon	plc,	Aon	Corporation	and	The	Bank	of	New	York	Mellon	Trust Company,	National	Association,	as	trustee	(including	the	Guarantee)	-	incorporated	by	reference	to	Exhibit	4.1	to	Aon's	Current	Report	on Form	8-K	filed	on	May	20,	2015.

4.20* Indenture,	dated	as	of	November	13,	2015,	among	Aon	plc,	Aon	Corporation	and	The	Bank	of	New	York	Mellon	Trust	Company,	N.A.,	as trustee	(including	the	guarantee)	-	incorporated	by	reference	to	Exhibit	4.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	November	13,	2015.

4.23* Indenture,	dated	as	of	December	3,	2018,	among	the	Company,	the	Guarantor	and	The	Bank	of	New	York	Mellon	Trust	Company,	N.A.,	as trustee	(including	the	guarantee)	-	incorporated	by	reference	to	Exhibit	4.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	December	3,	2018.

# Material	Contracts.

10.1* Amended	and	Restated	Agreement	among	the	Attorney	General	of	the	State	of	New	York,	the	Superintendent	of	Insurance	of	the	State	of New	York,	the	Attorney	General	of	the	State	of	Connecticut,	the	Illinois	Attorney	General,	the	Director	of	the	Illinois	Department	of	Insurance, and	Aon	Corporation	and	its	subsidiaries	and	affiliates	effective	as	of	February	11,	2010	—	incorporated	by	reference	to	Exhibit	10.1	to	Aon's Current	Report	on	Form	8-K	filed	on	February	16,	2010.

10.2* $900,000,000	Five-Year	Credit	Agreement	among	Aon	plc,	Aon	Corporation	and	Aon	UK	Limited	with	Citibank,	N.A.,	as	administrative agent,	the	lenders	party	thereto,	Bank	of	America,	N.A.	and	Morgan	Stanley	Senior	Funding,	Inc.,	as	syndication	agents,	and	Citigroup	Global Markets,	Inc.,	Merrill	Lynch,	Pierce,	Fenner	&	Smith	Incorporated	and	Morgan	Stanley	Senior	Funding,	Inc.,	as	joint	lead	arrangers	and	joint book	managers	entered	into	on	February	2,	2015,	-	incorporated	by	reference	to	Exhibit	10.1	to	Aon's	Current	Report	on	Form	8-K	filed	on February	4,	2015.

10.3* Form	of	notice	of	extension	of	$900,000,000	Five-Year	Credit	Agreement	among	Aon	plc,	Aon	Corporation	and	Aon	UK	Limited	with Citibank,	N.A.,	as	administrative	agent,	the	lenders	party	thereto,	Bank	of	America,	N.A.	and	Morgan	Stanley	Senior	Funding,	Inc.,	as syndication	agents,	and	Citigroup	Global	Markets,	Inc.,	Merrill	Lynch,	Pierce,	Fenner	&	Smith	Incorporated	and	Morgan	Stanley	Senior Funding,	Inc.,	as	joint	lead	arrangers	and	joint	book	managers	entered	into	on	February	2,	2015,	-	incorporated	by	reference	to	Exhibit	10.1	to Aon's	Quarterly	Report	on	Form	10-Q	for	the	quarter	ended	March	31,	2016.

10.4* Amendment	No.	1	to	the	February	2,	2015	Credit	Agreement	among	Aon	plc,	Aon	Corporation	and	Aon	UK	Limited,	the	banks,	financial institutions	and	other	institutional	lenders	party	to	the	Credit	Agreement,	dated	June	21,	2017,	incorporated	by	reference	to	Exhibit	10.3	to Aon's	Quarterly	Report	on	10-Q	for	the	quarter	ended	June	30,	2017.

10.5* $400,000,000	Five-Year	Credit	Agreement	among	Aon	plc	and	Aon	Corporation	with	Citibank,	N.A.,	as	administrative	agent,	the	lenders	party thereto,	HSBC	Bank	USA,	National	Association,	as	syndication	agent,	and	Citigroup	Global	Markets,	Inc.	and	HSBC	Securities	(USA)	Inc.,	as joint	lead	arrangers	and	joint	bookrunners,	entered	into	on	October	19,	2017,	incorporated	by	reference	to	the	Current	Report	on	Form	8-K	filed on	October	20,	2017.

10.6* Purchase	Agreement,	dated	as	of	February	9,	2017,	by	and	between	Aon	plc	and	Tempo	Acquisition,	LLC-	incorporated	by	reference	to	Aon's Current	Report	on	Form	8-K	filed	February	10,	2017.

10.7* Amendment	No.	1	to	Purchase	Agreement	by	and	between	Aon	plc	and	Tempo	Acquisition,	LLC,	entered	into	on	April	17,	2017,	incorporated by	reference	to	Exhibit	10.2	to	Aon's	Quarterly	Report	on	10-Q	for	the	quarter	ended	March	31,	2017.

10.8* Deed	of	Assumption	of	Aon	plc	dated	April	2,	2012	-	incorporated	by	reference	to	Exhibit	10.7	to	Aon's	Current	Report	on	Form	8-K	filed	on April	2,	2012.

10.9*# Aon	Corporation	Outside	Director	Corporate	Bequest	Plan	(as	amended	and	restated	effective	January	1,	2010)	—	incorporated	by	reference	to Exhibit	10.1	to	Aon's	Quarterly	Report	on	Form	10-Q	for	the	quarter	ended	June	30,	2010.

10.10*# Aon	Stock	Incentive	Plan,	as	amended	and	restated	—	incorporated	by	reference	to	Exhibit	10.2	to	the	Current	Report	on	Form	8-K	filed	on May	24,	2006.

10.11*# First	Amendment	to	the	Amended	and	Restated	Aon	Stock	Incentive	Plan	—	incorporated	by	reference	to	Exhibit	10(au)	to	Aon's	Annual Report	on	Form	10-K	for	the	year	ended	December	31,	2006.

10.12*# Second	Amendment	to	the	Amended	and	Restated	Aon	Stock	Incentive	Plan,	dated	April	2,	2012	—	incorporated	by	reference	to	Exhibit	10.10 to	Aon's	Current	Report	on	Form	8-K	filed	on	April	2,	2012.

10.13*# Aon	Stock	Award	Plan	(as	amended	and	restated	through	February	2000)	—	incorporated	by	reference	to	Exhibit	10(a)	to	Aon's	Quarterly Report	on	Form	10-Q	for	the	quarter	ended	June	30,	2000.

10.14*# First	Amendment	to	the	Aon	Stock	Award	Plan	(as	amended	and	restated	through	2000)	—	incorporated	by	reference	to	Exhibit	10(as)	to Aon's	Annual	Report	on	Form	10-K	for	the	year	ended	December	31,	2006.

10.15*# Aon	plc	2011	Incentive	Plan,	as	amended	and	restated	effective	June	24,	2014	-	incorporated	by	reference	to	Exhibit	10.1	to	Aon's	Quarterly Report	on	Form	10-Q	for	the	quarter	ended	June	30,	2014.

10.16*# First	Amendment	to	the	Aon	plc	2011	Incentive	Plan,	as	amended	and	restated,	effective	as	of	March	31,	2016	-	incorporated	by	reference	to Exhibit	10.9	to	Aon's	Quarterly	Report	on	Form	10-Q	for	the	quarter	ended	March	31,	2016.

10.17*# Executive	Committee	Incentive	Compensation	Plan	-	incorporated	by	reference	to	Exhibit	10.3	to	Aon's	Quarterly	Report	on	Form	10-Q	for	the quarter	ended	March	31,	2016.

10.18*# Aon	plc	Leadership	Performance	Program	-	incorporated	by	reference	to	Exhibit	10.2	to	Aon's	Quarterly	Report	on	Form	10-Q	for	the	quarter ended	March	31,	2016.

10.19*# Aon	Plc	Leadership	Performance	Program	as	amended	and	vested	effective	January	1,	2018	-	-	incorporated	by	reference	to	Exhibit	10.1	to Aon's	Quarterly	Report	on	Form	10-Q	for	the	quarter	ended	March	31,	2018.

10.20*# Aon	plc	Amended	and	Restated	Executive	Committee	Combined	Severance	and	Change	in	Control	Plan,	effective	September	12,	2016	- incorporated	by	reference	to	Exhibit	10.1	to	Aon's	Quarterly	Report	on	Form	10-Q	for	the	quarter	ended	September	30,	2016.

10.21*# Form	of	Deed	of	Indemnity	for	Directors	of	Aon	plc	—	incorporated	by	reference	to	Exhibit	10.4	to	Aon's	Current	Report	on	Form	8-K	filed on	April	2,	2012.

10.22*# Form	of	Deed	of	Indemnity	for	Gregory	C.	Case	—	incorporated	by	reference	to	Exhibit	10.5	to	Aon's	Current	Report	on	Form	8-K	filed	on April	2,	2012.

10.23*# Form	of	Deed	of	Indemnity	for	Executive	Officers	of	Aon	plc	—	incorporated	by	reference	to	Exhibit	10.6	to	Aon's	Current	Report	on	Form	8- K	filed	on	April	2,	2012.

10.24*# Form	of	Service	as	a	Non-Executive	Director	Agreement	-	incorporated	by	reference	to	Exhibit	10.2	to	Aon's	Quarterly	Report	on	Form	10-Q for	the	quarter	ended	September	30,	2016.

10.25*# Employment	Agreement	dated	April	4,	2005	between	Aon	and	Gregory	C.	Case	-	incorporated	by	reference	to	Exhibit	10.1	to	Aon's	Quarterly Report	on	Form	10-Q	for	the	quarter	ended	March	31,	2005.

10.26*# Amended	and	Restated	Employment	Agreement	dated	as	of	November	13,	2009	between	Aon	and	Gregory	C.	Case	-	incorporated	by	reference to	Exhibit	10.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	November	17,	2009.

10.27*# Amended	and	Restated	Employment	Agreement,	dated	as	of	January	16,	2015,	by	and	between	Aon	plc,	Aon	Corporation	and	Gregory	C.	Case -	incorporated	by	reference	to	Exhibit	10.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	January	23,	2015.

10.28*# Amendment	to	Employment	Agreement,	dated	April	20,	2018,	by	and	among	Aon	plc,	Aon	Corporation,	and	Gregory	C.	Case-	-	incorporated by	reference	to	Exhibit	10.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	April	25,	2018.

10.29*# Amendment	to	Employment	Agreement,	dated	May	10,	2018,	by	and	among	Aon	plc,	Aon	Corporation,	and	Gregory	C.	Case	-	incorporated	by reference	to	Exhibit	10.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	May	15,	2018.

10.30*# Amended	and	Restated	Change	in	Control	Agreement	dated	as	of	November	13,	2009	between	Aon	and	Gregory	C.	Case	-	incorporated	by reference	to	Exhibit	10.2	to	Aon's	Current	Report	on	Form	8-K	filed	on	November	17,	2009.

10.31*# Amendment	to	the	Amended	and	Restated	Change	of	Control	Agreement	between	Aon	plc	and	Gregory	C.	Case,	dated	as	of	April	27,	2016	- incorporated	by	reference	to	Exhibit	10.11	on	Aon's	Quarterly	Report	on	Form	10-for	the	quarter	ended	March	31,	2016.

10.32*# International	Assignment	Letter	with	Gregory	C.	Case,	effective	July	1,	2016	-	incorporated	by	reference	to	Exhibit	10.1	to	Aon's	Quarterly Report	on	Form	10-Q	for	the	quarter	ended	June	30,	2016.

10.33*# Amendment	to	International	Assignment	Letter,	dated	June	25,	2018,	with	Gregory	C.	Case	-	incorporated	by	reference	to	Exhibit	10.2	to Aon's	Current	Report	on	Form	8-K	filed	on	June	27,	2018.

10.34*# Employment	Agreement	dated	as	of	October	3,	2007	between	Aon	Corporation	and	Christa	Davies	-	incorporated	by	reference	to	Exhibit	10.1 to	Aon's	Current	Report	on	Form	8-K	filed	on	October	3,	2007.

10.35*# Amendment	effective	as	of	March	27,	2012	to	Employment	Agreement	between	Aon	Corporation	and	Christa	Davies	dated	as	of	October	3, 2007	-	incorporated	by	reference	to	Exhibit	10.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	March	30,	2012.

10.36*# Amendment	to	Employment	Agreement,	dated	April	19,	2018,	by	and	between	Aon	Corporation	and	Christa	Davies	-	incorporated	by	reference to	Exhibit	10.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	April	25,	2018.

10.37*# International	Assignment	Letter	with	Christa	Davies,	effective	July	1,	2016	-	incorporated	by	reference	to	Exhibit	10.2	to	Aon's	Quarterly Report	on	Form	10-Q	for	the	quarter	ended	June	30,	2016

10.38*# Amendment	to	International	Assignment	Letter,	dated	June	25,	2018,	with	Christa	Davies	-	incorporated	by	reference	to	Exhibit	10.1	to	Aon's Current	Report	on	Form	8-K	filed	on	June	27,	2018.

10.39*# Employment	Agreement	dated	December	7,	2010,	between	Aon	Corporation	and	Stephen	P.	McGill	-	incorporated	by	reference	to	Exhibit	10.1 to	Aon's	Current	Report	on	Form	8-K	filed	on	December	13,	2010.

10.40*# Amended	and	Restated	Employment	Agreement,	dated	as	of	July	8,	2015,	by	and	between	Aon	Corporation	and	Stephen	P.	McGill	- incorporated	by	reference	to	Exhibit	10.1	to	Aon's	Current	Report	on	Form	8-K	filed	on	July	14,	2015.

10.41*# International	Assignment	Letter	with	Stephen	P.	McGill,	effective	July	1,	2016	-	incorporated	by	reference	to	Exhibit	10.3	to	Aon's	Quarterly Report	on	Form	10-Q	for	the	quarter	ended	June	30,	2016.

10.42*# Separation	Agreement	entered	into	between	Aon	Corporation	and	Stephen	McGill,	dated	January	24,	2017,	incorporated	by	reference	to Exhibit	10.1	to	Aon's	Quarterly	Report	on	10-Q	for	the	quarter	ended	March	31,	2017.

10.43*# International	Assignment	Letter	with	Peter	Lieb,	effective	July	1,	2016	-	incorporated	by	reference	to	Exhibit	10.4	to	Aon's	Quarterly	Report	on Form	10-Q	for	the	quarter	ended	June	30,	2016.

10.44*# Employment	Agreement	dated	as	of	September	30,	2010	between	Aon	Corporation	and	Kristi	Savacool	-	incorporated	by	reference	to Exhibit	10.8	to	Aon's	Quarterly	Report	on	Form	10-Q	for	the	quarter	ended	March	31,	2012.

10.45*# Amendment	to	Employment	Agreement	dated	as	of	May	16,	2011	between	Aon	Corporation	and	Kristi	Savacool	-	incorporated	by	reference	to Exhibit	10.9	to	Aon's	Quarterly	Report	on	Form	10-Q	for	the	quarter	ended	March	31,	2012.

10.46*# Amended	and	Restated	Employment	Agreement,	dated	as	of	February	24,	2015,	by	and	between	Aon	Corporation	and	Kristi	Savacool	- incorporated	by	reference	to	Exhibit	10.2	to	Aon's	Current	Report	on	Form	8-K	filed	on	February	26,	2015.

10.47*# Transition	and	Separation	Agreement	entered	into	between	Aon	Corporation	and	Kristi	Savacool,	dated	April	25,	2017,	incorporated	by reference	to	Exhibit	10.1	to	Aon's	Quarterly	Report	on	10-Q	for	the	quarter	ended	June	30,	2017.

10.48*# Employment	Letter	with	Michael	O'Connor	effective	March	1,	2018,	incorporated	by	reference	to	Exhibit	10.4	to	Aon's	Quarterly	Report	on 10-Q	for	the	quarter	ended	March	31,	2018.

10.49*# Letter	Agreement,	dated	May	11,	2018,	by	and	between	Aon	Corporation	and	Michael	O'Connor,	-	incorporated	by	reference	to	Exhibit	10.2	to Aon's	Current	Report	on	Form	8-K	filed	on	May	15,	2018.

10.50*# Letter	Agreement,	dated	May	11,	2018,	by	and	between	Aon	Corporation	and	Eric	Andersen-	incorporated	by	reference	to	Exhibit	10.3	to Aon's	Current	Report	on	Form	8-K	filed	on	May	15,	2018.

10.51*# Aon	Deferred	Compensation	Plan,	as	amended	and	restated	November	16,	2016,	incorporated	by	reference	to	the	Annual	Report	on	Form	10-K for	the	year	ended	December	31,	2016.

10.52*# First	Amendment	to	the	Aon	Deferred	Compensation	Plan,	effective	December	8,	2016,	incorporated	by	reference	to	the	Annual	Report	on Form	10-K	for	the	year	ended	December	31,	2016.

10.53*# Second	Amendment	to	the	Aon	Deferred	Compensation	Plan,	effective	April	19,	2017,	incorporated	by	reference	to	Exhibit	10.1	to	Aon's Quarterly	Report	on	Form	10-Q	for	the	quarter	ended	June	30,	2017.

10.54*# Aon	plc	Global	Share	Purchase	Plan	effective	July	1,	2013,	incorporated	by	reference	to	the	Proxy	Statement	for	the	Annual	Meeting	of Shareholders	held	on	May	17,	2013,	filed	on	April	1,	2013.

10.55*# First	Amendment	to	the	Aon	plc	Global	Share	Purchase	Plan,	effective	November	17,	2017	-	incorporated	by	reference	to	Exhibit	10.49	to Aon's	Annual	Report	on	Form	10-K	for	the	year	ended	December	31,	2017.

10.56*# Form	of	Restricted	Stock	Unit	Award	Agreement,	incorporated	by	reference	to	Exhibit	10.51	to	Aon's	Annual	Report	on	Form	10-K	for	the year	ended	December	31,	2016.

10.57*# Aon	Supplemental	Savings	Plan,	Amended	and	Restated	Effective	January	1,	2017,	incorporated	by	reference	to	Exhibit	10.52	to	Aon's Annual	Report	on	Form	10-K	for	the	year	ended	December	31,	2016.

10.58*# First	Amendment	to	the	Aon	Supplemental	Savings	Plan,	Amended	and	Restated	effective	January	1,	2017,	effective	March	30,	2017, incorporated	by	reference	to	Exhibit	52	to	Aon's	Annual	Report	on	Form	10-K	for	the	year	ended	December	31,	2017.

# Subsidiaries	of	the	Registrant.

21 List	of	Subsidiaries	of	Aon.

# Consents	of	Experts	and	Counsel.

23 Consent	of	Ernst	&	Young	LLP.

31.1. Rule	13a-14(a)	Certification	of	Chief	Executive	Officer	of	Aon	in	accordance	with	Section	302	of	the	Sarbanes-Oxley	Act	of	2002.

31.2. Rule	13a-14(a)	Certification	of	Chief	Financial	Officer	of	Aon	in	accordance	with	Section	302	of	the	Sarbanes-Oxley	Act	of	2002.

# Section	1350	Certifications.

32.1. Section	1350	Certification	of	Chief	Executive	Officer	of	Aon	in	accordance	with	Section	906	of	the	Sarbanes-Oxley	Act	of	2002.

32.2. Section	1350	Certification	of	Chief	Financial	Officer	of	Aon	in	accordance	with	Section	906	of	the	Sarbanes-Oxley	Act	of	2002.

# XBRL	Exhibits.

Interactive	Data	Files.	The	following	materials	are	filed	electronically	with	this	Annual	Report	on	Form	10-K:

*				Document	has	been	previously	filed	with	the	Securities	and	Exchange	Commission	and	is	incorporated	herein	by	reference	herein.	Unless	otherwise	indicated,	such document	was	filed	under	Commission	File	Number	001-07933.

#				Indicates	a	management	contract	or	compensatory	plan	or	arrangement.

The	registrant	agrees	to	furnish	to	the	Securities	and	Exchange	Commission	upon	request	a	copy	of	(1)	any	long-term	debt	instruments	that	have	been	omitted pursuant	to	Item	601(b)(4)(iii)(A)	of	Regulation	S-K,	and	(2)	any	schedules	omitted	with	respect	to	any	material	plan	of	acquisition,	reorganization,	arrangement, liquidation	or	succession	set	forth	above.

# 								Pursuant	to	the	requirements	of	Section	13	or	15(d)	of	the	Securities	Exchange	Act	of	1934,	the	registrant	has	duly	caused	this	report	to	be	signed	on	its behalf	by	the	undersigned,	thereunto	duly	authorized.

	 Gregory	C.	Case,	Chief	Executive	Officer

Pursuant	to	the	requirements	of	the	Securities	Exchange	Act	of	1934,	this	report	has	been	signed	below	by	the	following	persons	on	behalf	of	the	registrant	and in	the	capacities	and	on	the	dates	indicated.



Question: what is the decrease observed in the additions for tax positions of prior years , in millions?
Calculation:   decrease = 12 - 10
 answer = decrease
Answer: 2