WHITE PAPER

Company Reporting in the UK– an XBRL Success Story

The use of eXtensible Business Reporting Language for company financial
reporting in the UK has proved an outstanding success. Some 1.9 million
UK companies file accounts and tax returns in XBRL each year.
The UK approach enables comprehensive and efficient reporting in XBRL
at low cost. It provides all the data required for analysis and comparison
by regulators and other users without a need for companies to create theirown effort-consuming XBRL ‘extensions’.
The UK success is founded on the use of the ‘Inline XBRL’ reporting format
and advanced taxonomies which enable comprehensive identification ofdata in XBRL.
This publication describes the UK XBRL programme and the factors behind
its success.

© XBRL UK 2015

Company reporting in the UK – an XBRL success story

CONTENTS
1.		Introduction		1
2.		 Key features and benefits		2
3.		 XBRL filing in the UK		4
		 3.1		Use of XBRL in the UK		 4
		 3.2		Creation of iXBRL reports		 5
		 3.3		Taxonomies and accounting regulations in the UK		 5
4.		 The role of Inline XBRL		7
5.		 Taxonomy design and the purpose of XBRL		9		 5.1 The UK approach		 9
		 5.2		Alternative approaches and company extensions		 96.		 UK taxonomy design – goals and requirements		11
		 6.1 Chief objectives		 11		 6.2		Scope of the taxonomies		 11		 6.3		Consistent data for analysis		 12
		 6.4		A complete data model – avoidance of company extensions		 12
		 6.5		Business requirements and cost issues		 127.		 UK taxonomy design – key features		13
8.		 Taxonomy presentation		16
		 8.1		The presentation view		 16
		 8.2		Display of dimensions		 17		 8.3 Labels		18
		 8.4 Viewing the UK taxonomies		 189.		 Taxonomy dimensions		19
		 9.1		 Scope of dimensions		 19
		 9.2		Use of dimensions		 1910.		 Achieving comprehensive tagging		21
		 10.1		Introduction		 21		 10.2		Analysis items		 21		 10.3		Non-standard dimension tags		 22		 10.4		Generic dimension tags		 23		 10.5 Groupings		23
11.		 Other taxonomy features		25
		 11.1 Guidance information		 25		 11.2 Text tagging		 26		 11.3 Technical features		 2612.		 Taxonomy structure, coverage and development		28
		 12.1 Structure and coverage		 28		 12.2 Future developments		 29		 12.3 Development process		 29Glossary				30
The XBRL UK jurisdiction		
33

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Company reporting in the UK – an XBRL success story.

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Company reporting in the UK – an XBRL success story

1.

Introduction

The publication explains the outstanding success of XBRL (eXtensible Business Reporting Language) forcompany financial reporting in the UK.
With some 1.9 million companies filling accounts and tax returns in XBRL each year, the UK XBRL
programme is by some way the largest in the world in terms of numbers of reports.
It is providing comprehensive company financial information in an “intelligent”, easily analysable
electronic format to both the tax authority, HMRC, and the business register, Companies House. The
latter is now publishing this company data in XBRL free-of-charge for investors and the public.
The use of XBRL in the UK has proved both efficient and cost-effective. The cost of filing in XBRL for
individual companies is far less than in some similar projects elsewhere.
This document describes the main features of the UK XBRL programme and the key factors behind
its success. It is intended for all those with an interest in the use of XBRL for financial reporting. In
particular, it may provide helpful background for those running or embarking on comparable projects
to use XBRL for company reporting.
It assumes readers already have a basic understanding of the nature and purpose of XBRL. General
information on XBRL is available on the XBRL international website at https://www.xbrl.org/.
For more information on the topics in this publication, please contact XBRL UK via email at:
info@xbrl.org.uk

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Company reporting in the UK – an XBRL success story

2. Key features and benefits
Two key features have contributed to the success of XBRL in the UK.

•

The use of the ‘Inline XBRL’, or iXBRL, format for reporting.
Under Inline XBRL, all XBRL data is contained within ordinary, human-readable files. Thesefiles are presented in HTML, the format of the web. This enables a single iXBRL report to operate
as both a standard set of accounts which may be viewed on screen or printed, and as a file of
XBRL ‘tagged’ data which can be analysed automatically by software.
An individual company can thus present its accounts in exactly the way it wishes. No additional
mechanisms are required to convert an XBRL filing into a human-readable form, saving
complexity and cost.
A company simply creates its accounts in a normal way and uses software to embed computerreadable XBRL tags within the report. The accounts are then said to be ‘tagged’ in XBRL.

•Innovative UK taxonomy design.
Taxonomies are the ‘dictionaries’ of XBRL, which define the computer-readable tags that identify
individual items of financial data. Their design is critical to the scope, efficiency and usefulness
of XBRL tagged data.
The UK XBRL taxonomies use a variety of techniques to enable a comprehensive range ofaccounting data, including company-specific, unusual and unexpected information, to betagged easily, quickly and consistently in XBRL.

Taken together, these two factors have a further major benefit:•

Company-specific taxonomy extensions are NOT required for UK XBRL filing.
Some XBRL projects require companies to create their own ‘company taxonomy extensions’ tocover information which is specific to the company concerned or to enable a human-readable
version of the accounts to be produced. (Taxonomy extensions add tags to or modify a basic
taxonomy published by a national or similar authority.)In the UK programme, such extensions are not necessary. The use of iXBRL means that reports
are already presented as the company wishes – no company-specific extension is required tohelp convert a set of XBRL data into a readable form. The innovative techniques used in the UK
taxonomies also allow comprehensive and consistent tagging of accounts, without the need for
additional company-specific XBRL tags.

	The avoidance of extensions greatly saves cost and effort for companies. It also avoids theconsiderable difficulties for comparison and analysis that company extensions may cause.
These features have enabled the UK XBRL programme to:• 	Ensure that all data relevant to analysis and comparison in company accounts can be clearly andaccurately represented in XBRL.

• 	Provide data that is represented in XBRL in a coherent and consistent way. This enables analysis
and comparison of company information that is practical, efficient and useful.

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Company reporting in the UK – an XBRL success story• 	Promote ease-of-use of XBRL, keeping down cost and effort for reporting companies andother users. It has not imposed unreasonable or unnecessary burdens on either producers or
consumers of information and has provided value for money for organisations, particularly
government bodies, supporting the programme.

Underlying these technical features is a cooperative approach to governance and use of XBRL in
the UK. Committees which oversee the development of taxonomies bring together representatives ofgovernment, regulators, other official agencies, accounting firms and software providers.
The practical features of the UK programme and the ease of iXBRL implementation have enabled awide range of software companies to offer applications for filing reports in XBRL. Users have a good
choice of tools and technical support.
The next section, section 3, describes the scope and nature of the UK XBRL programme.
Section 4 provides an overview of Inline XBRL. (A separate document, ‘Inline XBRL – Saving cost andeffort for company reporting’, gives more detail on the nature, uses and benefits of Inline XBRL. It isavailable on the XBRL UK website at http://www.xbrl.org.uk/.)
Section 5 explains the general principles underlying UK taxonomy design and how these relate to the
purpose of XBRL – the provision of financial data for automated handling and analysis by software. It
also sets out the reasons for avoiding company-level extension taxonomies.
Sections 6 to 12 describe the design, benefits and development of the UK taxonomies.
Other documents giving more technical detail on the taxonomies, including a Tagging Guide and a
Developer Guide, are available on the UK Financial Reporting Council website at https://xbrl.frc.org.
uk/.
The latest UK accounts taxonomies may be viewed over the internet at https://uk-taxonomies-tdp.
corefiling.com/yeti. This shows the ‘presentation view’ of each taxonomy together with the details of
individual tags. (It does not show all technical features of the taxonomies.)

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Company reporting in the UK – an XBRL success story

3. XBRL filing in the UK
3.1 Use of XBRL in the UK
UK companies have been required since April 2011 to file their annual accounts and corporation tax
return in iXBRL to the tax authority, HMRC. Some 1.9 million companies are now successfully filingthis information each year.
The accounts range from complex ones from large organisations to simple reports from small companies.
They vary significantly in format and presentation, since they are filed under principle-based accounting
standards which do not prescribe the layout of accounts. Most are filed under UK GAAP standards,
but a small number of large companies file under International Financial Reporting Standards, IFRS.
As a concession to ease the introduction of XBRL, HMRC initially set a ‘reduced tagging requirement’.
This allowed companies to use a reduced set of tags from the UK taxonomies at that time, rather
than the full set of tags. However, HMRC encouraged full tagging and a number of companies andaccounting firms followed full rather than reduced tagging. Under the latest taxonomies, all companies
are required to provide fully tagged data.
HMRC uses XBRL data to assess accounts and tax returns, help guide tax risk and policy decisions, judge
the consequences of legal challenges and gain a better understanding of the business population. Itsays that iXBRL filing has been extremely successful:“iXBRL enhances understanding of the taxpayer base; allows better targeting of interventions; saves
clerical resource and improves accuracy; makes accounts and computations accessible to computerized
analysis tools,” HMRC said recently. “XBRL tagged data is a powerful resource. Exploitation of thedata will become increasingly central to HMRC’s compliance assurance, risk assessment and analysis
functions.”
The UK business register, Companies House, which collects and publishes accounts from all UK
entities, has encouraged voluntary filing of accounts in XBRL for a decade. It began accepting simple,
small company accounts that followed a standard pattern in XBRL in 2005. It upgraded its systems from2011 to handle all accounts in iXBRL.
Some 70% of UK companies now file voluntarily in XBRL to Companies House and this proportion issteadily increasing.
In 2013, for the benefit of investors, financial institutions and the public, Companies House began
publishing free-of-charge all the iXBRL accounts it receives. The service now supports a variety ofinterfaces for searching and comparing UK company data. The government said the service
represented a commitment to open access and transparency which “can benefit everyone – whether it’sentrepreneurs, taxpayers, businesses or the public sector. Better data efficiency encourages innovation,delivers better public services and stimulates growth through new revenue streams.”
Other government departments and official bodies are now implementing or actively planning
XBRL projects. Some, such as a project led by the Charity Commission, which regulates charities inEngland and Wales, involve new filing of accounts in XBRL. Other projects involve sharing and using
accounts information which is already being filed to HMRC or Companies House.

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Company reporting in the UK – an XBRL success story

3.2 Creation of iXBRL reports
The creation of iXBRL reports has become a standard feature of UK accounts and tax software.
Accounts production software for smaller companies with less complex accounts will create iXBRL
reports automatically. Users enter accounts data in their normal manner. They need have no special
knowledge of XBRL and may even be unaware of XBRL tagging. Such software generally uses flexible
templates that tie accounting data to the correct tags ‘behind the scenes’. Users face no additionalcosts or effort in creating accounts in iXBRL format.
Preparers of more complex accounts, which typically will be in spreadsheet or document form, will use
tagging software to apply tags to the accounts. Such software may rely entirely on manual tagging
or may include some automated processes which suggest correct tagging to users. The users of such
software will require some XBRL expertise.
Some larger companies with more complex accounts have set-up iXBRL production in-house, whileothers have used their accounting firms or other third party organisations to convert accounts to iXBRL.
Costs of third party services vary with the size and number of accounts being handled. However, they
are a small fraction of the typical costs in comparable programmes elsewhere which require company
extension taxonomies.

3.3 Taxonomies and accounting regulations in the UK
Mandatory filing of accounts in the UK began in 2011 with two main taxonomies, a UK GAAP taxonomy
and a UK IFRS taxonomy. The vast majority of companies filed under UK GAAP, while publicly quoted
organisations used IFRS. The UK GAAP and UK IFRS taxonomies were similar in design and size, butwith different tags to reflect the differing requirements under the two sets of standards.
The taxonomies were developed by XBRL UK, the UK arm of XBRL International, with support from
HMRC and Companies House. Ownership of these taxonomies was transferred in 2013 to the
Financial Reporting Council (FRC), the regulatory body which sets accounting standards in the UK
and Republic of Ireland.
In 2014, the FRC published three new taxonomies to handle new accounting standards taking force inthe UK and Ireland. These taxonomies are:Full IFRS	For accounts under EU-adopted IFRS. This principally covers the consolidated
accounts of listed organisations.
FRS 101

 or the new FRS 101 accounting standard. This is for subsidiaries and parents of listed
F
organisations. It allows some exemptions from disclosures required under full IFRS.

FRS 102	For the new FRS 102 standard. This is for all other companies above the small
company threshold and is based on the version of IFRS for small and medium entities.
It effectively replaces the old UK GAAP standards.
From the start of 2015, all UK companies above the ‘smaller entity’ threshold are required to use thesestandards. Some have already early-adopted FRS 101 and 102. The FRC is also consulting on new
regulations for small and micro entities developed from FRS 102. These will give the UK and Irelanda coherent set of standards founded on IFRS. Additional taxonomies will be developed for small andmicro entities.

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Company reporting in the UK – an XBRL success story

The three new taxonomies, Full IFRS, FRS 101 and FRS 102, are all based on a common coretaxonomy, since they are all based on IFRS principles and concepts. They thus:•

Share a large range of common tags.

•

Follow identical designs.

•

 ontain the same components for standard company information and reports such as the Audit
C
Report and Directors’ Report.

•

Contain sections to handle particular industry sectors.

Their design and content represents an evolution from the original taxonomies used from 2011. They
reflect the experience gained during the first phase of mandatory XBRL use from 2011 to 2014.
After the next section on Inline XBRL, the rest of this document is focused on explaining the design,
benefits and development of these taxonomies.

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Company reporting in the UK – an XBRL success story

4. The role of Inline XBRLAccounts prepared in Inline XBRL, generally known as ‘iXBRL’, appear to human readers as normal
financial reports. The accounts are shown in HTML, the language of internet pages, exactly in the form
in which the company wishes to present them. They can be read in any browser.
XBRL tags for specific items of information are embedded in a hidden layer in the HTML file. They canbe displayed by software whenever users wish to see them and processed and analysed by software in
the normal way.
iXBRL thus handles both the presentation of accounts and the delivery of XBRL data in a single file.
By contrast, the alternative form of delivering XBRL information, which consists of a file of raw XBRL
data known as an ‘instance document’, requires additional mechanisms to make a report readable.
Such files purely contain XBRL data without any presentational structure. These may be suitable for datathat is entirely reported through fixed templates or tables in spreadsheets, which can be used to handle
presentation. However, they are much less suitable for handling company accounts and other reports
which follow highly flexible and variable formats.
The UK programme has found that iXBRL provides an ideal solution for handling of company
accounts which follow variable formats. It gives a range of major benefits:a.

PresentationiXBRL provides a straightforward solution to the presentation of XBRL reports. It enables users
to see data arranged and formatted as intended by the preparer. It removes the need for otherpresentational mechanisms, which typically add great complexity, effort and cost.

b.

Accuracy of XBRL tagging
A display of an iXBRL report can show the original text with associated XBRL tags alongside. Thisis a major aid to checking the accuracy and consistency of XBRL tagging.

c.

Avoiding unnecessary XBRL tagging and reducing tagging effort
iXBRL allows data to be reported as ordinary text without XBRL tagging. Only data which is
required for analysis and comparison by software need be tagged. Other information
is simply delivered as ordinary text as part of the Inline XBRL document. It does not have to betagged in order to transmit it to consumers or enable the presentation of accounts to be rebuilt.
This avoids users having slavishly to apply XBRL tags to highly company-specific, supplementaryor other data that is not appropriate for software analysis. For example, long textual statements,
such as business reviews which contain extensive content that is not suitable for XBRL representation
and are best read in their original form, can be left largely or wholly untagged.
This significantly reduces the cost and effort of XBRL implementation and use.

d.

Phasing and simplifying the introduction of XBRLRegulators and other agencies can ‘phase’ their introduction of XBRL, initially requiring only
a limited proportion of data to be tagged, while still receiving full reports. Tagging may be
expanded flexibly as required in later phases in the light of experience. This approach enables
the proportionate and cost-effective introduction of XBRL.

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Company reporting in the UK – an XBRL success storye.

Simplifying the design and content of taxonomies
Taxonomies need not be designed to cover the requirements of presentation or to ‘chase’unusual, highly company-specific or eccentric data. They can be designed and scaled purely tocover data which is required for automated analysis. This greatly simplifies the development anduse of taxonomies.

f.

Easing the task of software development
Software development for iXBRL is relatively straightforward. iXBRL avoids the complexities
imposed by other approaches.
By using HTML, the language of the web, for delivering reports, iXBRL is employing an open,
freely available standard which is well understood by software companies. This greatly reduces
development expense and risk. It has encouraged the creation of a broad range of software
products to handle iXBRL report production and consumption. Standard tasks such as display
and printing can be handled by ordinary, off-the-shelf software.

g.

Avoiding company extension taxonomies
Company extension taxonomies to cover unusual company-specific data or to define presentationand layout of accounts are not required.

In summary, iXBRL solves the issues of presentation of XBRL accounts, simplifies the application oftagging and design of taxonomies and greatly reduces cost and effort in XBRL reporting.

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Company reporting in the UK – an XBRL success story

5. Taxonomy design and the purpose of XBRL
5.1

The UK approach

The purpose of XBRL is to enable the automated analysis and handling of financial data by software.
However, this analysis can prove challenging, particularly if data is represented in incomplete orinconsistent ways.
The great variation in the content and format of company accounts means that business rules forcomparing and analysing data are often complex, even if the data is accurate and unambiguous. An
accounting item may be composed of very different components in different companies, even within asingle industry sector. Calculation pathways will vary correspondingly.
Nevertheless, it is possible to write useful comparison and analysis rules which will apply acrosscompanies, provided data definitions and relationships are clear and stable. Such rules bring great
rewards in terms of the transparency and understanding of company finances.
However, it becomes crushingly more difficult – if not impossible – to write useful and substantive rules
when data definitions and relationships are uncertain and shifting.
The UK taxonomies therefore aim to provide a complete, coherent and consistent model ofthe data in company accounts that is required for analysis.
They define all the tags that are required to be used for accounts. They also fix the relationships
between tags. For example, as explained in section 7, the relationship between tags representing line
items and the ‘dimension tags’ which represent the different forms in which data may be reported(typically the columns the financial tables) are entirely predefined and fixed.
Taxonomy design and rules for tagging seek to ensure there is only one clear and correct means oftagging any individual item of data – not multiple alternative means.
Analysis and comparison rules can thus be written on a firm basis. This does not mean that the UK rules
or the taxonomies are by any means flawless. Use in practice inevitably reveals gaps or weaknesses inavailable tags or their structure. However, these problems are generally marginal and may be dealt withover time, in the light of experience.
The UK taxonomies thus provide a sound basis for comparison and analysis of company data
which will steadily evolve and improve over time.
UK filings do not attempt to represent the calculations which individual companies may use in theiraccounts. Consumers are expected to define analysis and risk rules for their own purposes, given
the clear data definitions and relationships in the taxonomies. However, a set of consistency checks
published with the taxonomies, which describe summation and other relationships, provides a foundation
for checks on accurate tagging and analysis rules in software.
Sections 6-12 describe the design of the UK taxonomies. In particular, they explain how thetaxonomies can fully define all required XBRL tags, while being sufficiently flexible to cover
the myriad variations in format and content which may arise in company accounts.

5.2 Alternative approaches and company extensions
Some XBRL projects try to deal with the varied content in company accounts by allowing companies tocreate their own taxonomy extensions which add and amend tags and alter the relationships between
them. Companies then use these extensions to tag their accounts.

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Reviews of these projects show that even minor variations in taxonomies can wreak havoc with data
analysis rules – posing a huge challenge for consumers.
For example, apparently small changes in dimension tags, connections and definitions can radicallychange the way a taxonomy is applied.
The use of company extension taxonomies which make significant additions or amendments to basetaxonomies can thus deeply undermine predefined analysis and comparison. Almost by definition,companies will modify taxonomies in differing ways and will thus not provide consistent data for analysis.
Consumers are forced towards case-by-case analysis based on the peculiarities of the extensions
concerned.
This does not necessarily mean that company extension taxonomies can never be used or justified. But it
does mean that such extensions must work within very tightly defined rules which control what taxonomy
modifications are permitted.
However, this can only work if modifications are predictable. The UK programme has found it preferable
to build flexibility into its taxonomies to cover predictable variations in company reporting, forexample through the ‘analysis items’ and ‘generic dimensions’ explained in section 10, rather thanpermitting extensions.
The production and processing of company extensions inevitably increases the effort and cost involvedin preparing and consuming XBRL reports. It demands additional expertise, processes and investment
in software from preparers. It imposes a significant additional burden on consumers in handling andinterpreting such extensions. The UK programme has therefore always sought to avoid them.
The UK approach to Inline XBRL, taxonomy design and extensions will not suit all projects. Other
projects may operate under very different requirements and circumstances.
For example, the banking reporting programme in Europe under the European Banking Authority(EBA) defines requirements in the form of strictly defined spreadsheet templates. These determine thestructure and presentation of filings. Such filings do not need Inline XBRL to present reports.
However, the UK XBRL programme has found that the use of Inline XBRL and the taxonomy
design features set out in this publication have provided a very powerful and successful basefor the filing of company financial reports in XBRL.

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6. UK taxonomy design – goals and requirements
6.1 Chief objectives
The main objectives of the UK accounts taxonomies are to:a.

Define clearly and accurately the XBRL tags needed to identify specific items of information.

b.	Support comprehensive and cost-effective tagging of all data required for automated analysis,comparison and review by existing and expected consumers of XBRL reports.
c.

Be simple and efficient to use.

d.	Provide correct and consistent tagged information which can be used easily and effectively by
consumers of XBRL reports.
A number of important requirements and considerations are linked to these objectives. They are coveredin the next sections.

6.2 Scope of the taxonomies
The taxonomies are expected to enable:a.	Complete tagging of the monetary and numeric data in the schedules in the primary financial
statements and the notes or footnotes to the accounts.
b.	Tagging, for the purposes of identification, of all textual information which is important to theinterpretation and meaning of accounts. This means high-level tagging to indicate the presence
and scope of particular textual statements, but not necessarily granular tagging of the detailed
components of such statements.
Data may be excluded from detailed representation in the taxonomies if it meets at least two of thefollowing related criteria:i.

Very varied in content and form across companies.

ii.

Highly specialised – either in general or for the sector concerned.

iii.

Not expected to be useful for automated analysis by likely users of accounts.

These requirements are intended to achieve comprehensive tagging of all data required forautomated analysis and comparison. They deliberately exclude data which is so unusual orcompany-specific that it is unlikely to be open to comparison between companies or amenable toanalysis by any general application or predefined set of rules.
The UK view is that there is no point in imposing cost and implementation burdens in order to represent
numeric data in XBRL which in practice is not open to automated analysis.

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6.3 Consistent data for analysis
A key test of the UK taxonomies is whether they support tagging which is consistent across different
financial reports. Weakly designed taxonomies may support broad tagging by defining tags haphazardly,
but the latter will not produce data which can be handled efficiently by software.
An aim of UK taxonomy design is that there should only be one clear and correct means of tagging
any individual item of data – not multiple alternative means.
This aim is achieved not only through taxonomy design but also through the user guidance whichaccompanies the taxonomies. For example, this guidance sets rules on the correct choice of tags wheneffectively the same data is reported in primary statements and in notes to the accounts. (UK guidance
requires tags should match the intended level of detail or granularity of a disclosure. Broad total tags
should be used for items which effectively represent totals, as in primary statements, and granular tags
should be used to represent breakdowns in notes.)
This underlines that taxonomies cannot be considered in isolation but must be understood in conjunction
with the user guidance which accompanies them.

6.4 A complete data model – avoidance of company extensions
The UK taxonomies are intended to support all required tagging without any need for companyspecific taxonomy extensions. This reflects the general goals that tagged data must be easily analysedand compared and that tagging must be cost-effective. The problems presented by company extensions
are discussed in section 5.2.

6.5 Business requirements and cost issues
The design and content of the UK taxonomies are tied tightly to business considerations.
The scope of the taxonomies reflects the nature and extent of business requirements for the automatedanalysis and comparison of data.
Their design and use also reflect demands from business and government that the costs of XBRL
implementation must be rigorously controlled and justified.

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7.

UK taxonomy design – key features

The objectives and requirements for the UK taxonomies set out in the previous section are demanding
ones.
The requirement for comprehensive coverage of all data that may be needed for automated analysis,
without reliance on company extensions, means that use and content of the taxonomies must be fully
thought out and tested during the development stage.
All required tags must be predefined in the taxonomies and the structures of dimensions(explained under point b below) must be complete. Technically, the taxonomies must provide acomplete, coherent and consistent model of the data in accounts which should be tagged.
This must be achieved without creating cumbersome taxonomies containing very large numbers oftags that are hard to distinguish and manage. The taxonomies must be as easy as possible to use. They
must support accurate, clear and consistent tagging.
Key features which enable the UK taxonomies to meet their goals are listed below. They are explained
more fully in the subsequent sections. (The ordering below is for convenience: it does not reflect
importance. All these points are relevant to the success of the taxonomies.)a.

Presentation
The presentation view of a taxonomy is based directly on the structure of a normal set of accounts.
The structures of reports, primary statements and notes to the accounts will be immediatelyfamiliar to anyone accustomed to UK reporting. Within each section, the hierarchy of tags isdesigned to be simple and convenient to use on screen.
The sole aim of the presentation view is to make it easy for users to locate and identify tags.
It does not need to serve as a basis for the presentation of individual company accounts, sincethat is dealt with by iXBRL. This enables a cleaner and more effective view, since features needed
for handling the presentation of accounts are not required.
Section 8 gives more information on the presentation of UK taxonomies.

b.

Use of dimensions‘Dimensions’ are used in the UK taxonomies to represent the represent the different forms orclasses in which financial data may be reported. They identify standard breakdowns, such asthat for continuing or discontinued operations.
The large number of dimensions used in the taxonomies provide flexible and efficient coverageof accounting data. Each dimension contains a number of individual ‘dimension tags’ to identify
the specific breakdowns that may arise. For example, the dimension representing the classes
of property, plant and equipment (PPE) contains some 40 dimension tags, each identifying a
specific class.
Line item tags representing particular accounting concepts, such as revenue or profit, are tied tothe particular dimensions with which they may be used.
The relationships between line item tags and dimensions are fully defined in the UK
taxonomies. Each line item tag is connected to all the dimensions that are appropriate for it.
This provides a general structure of line item tags and dimensions which is expected towork across all companies, whatever individual financial tables they may create.

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Company reporting in the UK – an XBRL success story

Taxonomy users are presented with simple and sensible selections of dimension tags whentagging accounts or building analysis rules.
This is known as a ‘data-centric’ approach to defining and using dimensions. Alternative,
presentation-oriented approaches require preparers of XBRL reports to use extension taxonomies
to create dimensional structures to match the individual financial tables in a particular company’s
accounts.
Section 9 explains the use of dimensions in the UK taxonomies in more detail.
c.

Comprehensive tagging
The UK taxonomies use a variety of techniques to achieve tagging of unpredictable, companyspecific data. These provide a reliable means of tagging data which otherwise might need acompany taxonomy extension.
The techniques include:•

Analysis items

	Analysis items enable company-specific breakdowns of information which cannot be
predicted in advance to be tagged. They cover unusual or unexpected line items.
Technically, they rely on the use of a feature of dimensions known as ‘typed dimensions’.

•

Non-standard dimension tags

	‘Non-standard’ dimension tags enable unusual breakdowns of data represented bydimensions to be tagged. For example, they are used to handle unusual classes of PPE.

•

Generic dimension tags

	Generic dimensions tags are used to represent classes whose individual members
are specific to a company and cannot be fully defined in advance. Examples include
entity officers and directors, subsidiaries, associated companies and the like. Genericdimensions are tied to name tags so that companies can provide full identification of theindividual, company-specific items they are reporting.

•Groupings

	Groupings are used to handle sets of tags which are expected to be used in combination
and which may have to be repeated in a report to represent multiple occurrences of theinformation concerned. These are also handled by ‘typed dimensions’.
These techniques are described more fully in section 10 on comprehensive tagging.
d.

Other features
A number of other features improve the usability and accuracy of the UK taxonomies. These
include:•

Guidance, cross-reference tags, hyperlinking and other help within taxonomies

	Guidance tags contained within the taxonomy provide general information to users, forexample on how a set of tags should be applied.

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Company reporting in the UK – an XBRL success story

	Cross-reference items point to where tags for related information may be found. They
help users navigate efficiently through the taxonomy. Connections defined within thetaxonomies enable software to include hyperlinks in taxonomy displays, allowing users
to move easily between related sections.
	Documentation fields are attached to some individual tags to provide additional
information on how the tag should be used.
	All line item tags in the financial sections of the taxonomies contain accounting
references to authoritative publications defining the concept they represent. This helps toconfirm their intended meaning and use.

•

Text tags	A variety of types of text tags enable efficient tagging of textual information within reports.
All text tags define specific information. The taxonomies do not contain any ‘text block’
tags to cover large blocks of information.

•

Supporting documentation

	The taxonomies are supported by documents stating in detail how they should be used.
A Tagging Guide describes the features of the taxonomies and sets out rules for theapplication of tags under various circumstances. A Developer Guide explains thetaxonomies for the benefit of software developers. It sets out rules for the handling anddisplay of XBRL- related information by software.

•

Consistency checks

	A set of consistency checks representing some summation and similar relationships fortagged data have been published in spreadsheet form alongside the taxonomies. These
are intended to help software developers implement tests on the completeness andaccuracy of tagging.
Section 11 gives more detail on some of these features.
e.

Taxonomy coverage and structureT he main sections of the UK taxonomies are designed with normal commercial and industrial
companies in mind, but the taxonomies also contain additional sections for banking andfinance, investment funds and extractive industries.
Taxonomy extensions aimed at other industry sectors are expected to be published in due
course. Work or planning on several is already under way. It is accepted that UK taxonomies will
not cover every aspect of reporting by some specialist sectors for the time being. However, they
do not need to. Data can still be reported satisfactorily as text in Inline XBRL.
Taxonomies and tagging will be expanded as and when a business justification for automatedanalysis and comparison of the data concerned is put forward and accepted.
Section 12 sets out the structure of the taxonomies and describes their development.

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Company reporting in the UK – an XBRL success story

8. Taxonomy presentation
8.1 The presentation view
By following the typical structure and ordering of a set of accounts, the presentation view or ‘linkbase’provides users with an easily understandable display of a taxonomy. The figure below shows the toplevel sections of the FRS 102 taxonomy. (The numbers on sections are just for ordering.)

The arrangement of sections and tags should be very familiar to all those familiar with UK company
reporting. The following figure shows part of the notes section of the FRS 102 taxonomy.

Displays of tags are arranged with totals at the top of a hierarchy, with component items opening below
them. This provides the most efficient view on screen, with the most commonly used items
being the most visible and accessible. As an example, the following figure showing a partial view of
the FRS 102 ‘Debtors’ section. Component items are displayed below their totals.

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Company reporting in the UK – an XBRL success story

This approach to display is clean and easy-to-use, enabling the most important tags to be locatedquickly and efficiently. It can be achieved because the presentation view does not have to be used togenerate readable versions of individual company accounts. That is handled by Inline XBRL.
Taxonomies which have to support special mechanisms to create human-readable accounts from XBRL
data will typically require more complex presentation views. These may include more heading items andawkward hierarchies which place totals at the foot of their components in order to mimic the orderingin printed accounts. They may also require multiple label types such as total, negated, terse, verbose,
period start / end and the like in order to capture terminology variations in printed accounts.

8.2 Display of dimensions
The main sections of the presentation view of the UK taxonomies only show line item tags, together
with any required heading, guidance or cross-reference tags. Dimension tags are displayed in a
separate section (numbered 500, at the foot of the presentation view). That is purely to provide an
overview of available dimension tags.
Taxonomy software is expected to show the dimension tags which may be used with eachline item through a suitable display – typically a separate window or pop-up alongside thepresentation view. (The dimension tags which may be used with each line item are defined in a
separate part of the taxonomy: the definition view or ‘linkbase’.)For example, the figure below shows the dimensions connected to the line item tag ‘Disposals,
property, plant and equipment’ from the PPE movement analysis section. (For simplicity, only one of thedimensions, PPE ownership, is shown partly expanded, with its dimension tags.)

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Company reporting in the UK – an XBRL success story

It is not necessary or practical to show dimensional connections within the main body ofthe presentation view. Any attempt to represent specific financial tables which mix line items anddimension tags will inevitably fail since companies vary greatly in how they structure such tables. It is
not required for the presentation of individual accounts, since that is handled by iXBRL.
Instead, available dimensions are most efficiently displayed by taxonomy software. This enables
preparers to select all the dimensional options they may need to represent particular content or tables.

8.3 Labels
The quality of the labels of tags is critical to the efficiency and usability of taxonomies.
The labels in UK taxonomies are designed to identify items clearly and uniquely without being overlong
and clumsy. They use standard accounting terminology. Their content follows a number of styles andconventions to help users discern patterns and quickly recognise meaning. Only a single standard label
is needed to identify each tag.
Labels show whether values should be entered as positive or negative. They include terms in brackets
to show data which should be negative, as for example in ‘Operating profit (loss)’.
Terms in square brackets at the end of labels are used to enable users to distinguish different types oftags at a glance. Examples include [boolean], [guidance], [cross-reference] and the like. This helps toreinforce any distinctions made by technical means, such as the ‘datatype’ of tags.

8.4 Viewing the UK taxonomies
The latest UK accounts taxonomies can be viewed over the internet at https://uk-taxonomies-tdp.
corefiling.com/yetiThis shows the presentation view of each taxonomy and the details of individual tags. (It does not show
dimensional connections or other ‘definition linkbase’ relationships. Those may be seen in appropriate
taxonomy viewing software.)
The taxonomies may be downloaded from the FRC website at https://xbrl.frc.org.uk/.

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Company reporting in the UK – an XBRL success story

9. Taxonomy dimensions
9.1

Scope of dimensions

The UK accounts taxonomies contain some 90 dimensions to identify a very wide range of forms andclasses of data. Among other things, dimensions are used to distinguish:
Company and consolidated data•
Continuing and discontinued operations•
Classes of equity•
Classes of assets such as PPE, intangible assets and provisions•
Geographic, operating and other business segments•
Subsidiaries, joint-ventures and associates•
Acquisitions or business combinations•
Related parties•
Pension schemes; share-based payment arrangements••	A wide range of data related to financial instruments, including class of asset and liability,

various aspects of instrument type, derivative types and purpose, value type, current /non-current, maturity period, impairment allowance, risk exposure and the like.

•
•
•
•

Share classes and share types
Directors
Restated information, including prior period adjustments
Type and nature of the entity and various aspects of the financial report

Some dimensions are purely concerned with general distinctions, such as whether assets are owned orleased or whether inventories are current or non-current. Other dimensions may cover both general andspecific distinctions. For example, the related parties dimension enables the identification of generalclasses of related party, such as parent entities, other group members and key management personnel,
as well as specific related parties within each class.
The number of dimension tags in each dimension varies greatly. For example, the equity classes
dimension contains some 50 dimension tags representing individual types of reserve, while the group/company dimension contains just two, identifying group and company data.
This broad range of dimensions provides a powerful means of ensuring the UK taxonomies satisfactorily
cover the wide range of data that may appear in accounts.

9.2 Use of dimensions
The dimensions which may be used with any line item tag are fully defined in the taxonomies. This
makes the choice and use of dimension tags easy for users. Preparers of reports do not have tounderstand technical aspects of dimensions; they simply have to apply the tags made available to themby taxonomy software.
The taxonomies cover all combinations of line item and dimension tags required for XBRL reporting.
They do not permit combinations which are inappropriate under accounting standards or which makeno accounting sense.

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Company reporting in the UK – an XBRL success story

The taxonomies are not defined to represent specific financial tables, since tables may vary enormously
in format and content across companies. Instead, by defining general relationships between line itemand dimension tags, the taxonomies enable the easy and efficient tagging of data in lists or tables,
whatever their particular content and format.
Most line item tags are only connected in the taxonomies to a small number of dimensions. For
example, most PPE items are attached to five dimensions: PPE classes, PPE ownership, continuing /discontinued operations, group / company and restatements. These are shown in the figure in section
8.2. However, some financial instrument line items are attached to a significantly larger number ofdimensions, reflecting the complexity and flexibility of financial instrument reporting.
To make tagging easier for preparers of reports, most dimensions in the UK taxonomies contain a‘default’ dimension tag which is assumed to apply for a dimension, if a preparer does not actively
select a tag from the dimension. This saves preparers’ effort in applying tags. The default tag represents
the typical, expected meaning of a dimension. Generally, this will be a tag for a total value, althoughthat does not have to be the case.
The figure below shows the financial instrument current / non-current dimension with its total default.

Some dimensions contain the default tag ‘Not applicable’. This means that the dimension can effectively
be ignored, unless the user actively applies a tag from the dimension. This is useful when a dimension is
only sometimes relevant to the line items to which it is linked. For example, the dimension representing
different types of reclassification of financial assets has a ‘Not applicable’ default, because financial
assets may only sometimes be reclassified. The dimension may thus be tied to all financial asset line
items in the taxonomies, but is only applied when required.
This aids flexibility in pre-defining line item and dimension relationships in the taxonomies. It enables all
dimensions which may potentially be required with line items to be linked to them.

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Company reporting in the UK – an XBRL success story

10. Achieving comprehensive tagging
10.1 Introduction
As outlined in section 7, the UK taxonomies use a variety of techniques to achieve comprehensive
tagging of accounts, without requiring companies to create extension taxonomies to cover unusual or
unpredictable company-specific data. These techniques enable such data to be reliably identified andclassified with XBRL tags.
The techniques represent some innovations in taxonomy design, but are based on standard features of
the XBRL specification. They operate reliably for UK filing.

10.2 Analysis items
Tags known as ‘Analysis items’ are used tor tagging of entries in accounts for which no suitable line item
tag exists in the taxonomies.
As far as possible, the taxonomies provide specific tags for disclosures, so that most or all data inaccounts can be covered by ordinary, explicit line item tags. However, it is impossible to predict all
variations and breakdowns in reporting that individual companies may adopt. Analysis items handle
uncommon or unexpected breakdowns of information not covered by ordinary line item tags.
Each analysis item tag is specific to the section in which it appears. It is defined as representing acomponent of the total monetary or numeric value for the section. If necessary, it may be used repeatedly
to tag multiple entries in the section for which no line item tag exists.
The purpose of analysis items is to support complete tagging of the section in which they
appear. They thus enable summation and other automated analysis of the data in the section.
Analysis items have labels in a special format which enable users to identify them easily. They normally
begin with the word ‘Further’ and state the total of which they are a component. The figure below
shows the analysis item ‘Further item of cash and cash equivalents [component of total cash and cash
equivalents]’ in the cash and cash equivalents section of the taxonomy.

This analysis item may be used to tag the value of any type of cash and cash equivalent which isreported as a direct component of total cash and cash equivalents and is not represented byan available specific tag. For example, it could be used to cover detailed entries which replace thebanking arrangements entry. It could also cover aggregations, such as a combination of short-term
investments and short-term deposits. The analysis item should thus enable complete tagging of any
financial disclosure which shows a breakdown of cash and cash equivalents.
Analysis items are used in sections of primary statements and notes where unexpected line items may
occur, including main sections, sub-sections, movement analyses and other detailed disclosures.

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Company reporting in the UK – an XBRL success story

Aside from their role in covering unexpected data, analysis items operate in exactly the same way
as ordinary line item tags. They are attached to the same dimensions as other line item tags in thesection concerned, so they can represent the same forms and classes of data.
Technically, analysis item tags are attached to a special form of dimension, known as a ‘typed dimension’.
This enables each tag to be used multiple times to cover different entries in a section, if necessary, witheach use being individually identified.
In the UK, analysis items are not used in combination with a ‘name’ tag to describe the specific data forwhich they are used. It was felt this would require unnecessary effort from preparers, since any consumer
can check the inline XBRL text to see a description of the data represented by an analysis item. The lackof a description does not hinder automated numeric analysis. However, if required in other projects, aname tag could easily be associated with each analysis item tag, enabling a description to be attachedto each use.

10.3 Non-standard dimension tags
‘Non-standard’ dimension tags are included in some dimensions to cover untypical classes or
breakdowns which cannot be defined in advance.
They fulfil a similar role within dimensions to that handled by analysis items for line item tags. They may
be used to represent any class or breakdown which is (a) not covered by explicit tags in the dimensionand (b) a direct component of the total for the dimension.
They are only used in a limited number of dimensions where unexpected classes or categories may
arise. Only a small number of non-standard dimension tags are included in each of these dimensions,since ordinary dimension tags are expected to cover most eventualities. The following figure shows thenon-standard dimension tags included in the PPE classes dimension.

The existence of such tags enables full tagging of data and thus permits a range of automated tests
and rules on data to be run. They do not describe the specific class for which they are used. Consumers
have to read the Inline XBRL text for the description.

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Company reporting in the UK – an XBRL success story

10.4 Generic dimension tags
‘Generic’ dimension tags are used for classes of data whose individual members are company-specificand cannot be fully identified in advance. Examples include entity officers and directors, subsidiaries,
associated companies and the like.
Generic dimension tags represent such classes by numbered tags. For example, individual subsidiaries
are represented by the tags ‘Subsidiary 1’, ‘Subsidiary 2’ and so forth. The taxonomies contain sufficientof these tags in each class to cover all likely tagging requirements.
The following figure shows part of the subsidiaries dimension. The number of generic subsidiary tags
goes up to 50. (Some companies may have more than 50 subsidiaries, but the number listed in detailand needing tagging in their accounts is normally much less than this.)

Each set of generic dimension tags is associated with a name tag so that companies can provide full
identification of the individual, company-specific items they are reporting. For example, the subsidiaries
generic tags are tied to the line item tag ‘Name of subsidiary’.
A total of 16 dimensions in the UK accounts taxonomies contain some generic members. All also
include explicit dimension tags to cover totals or other information. Examples of the dimensions are:

•
•
•
•
•
•
•
•
•

Entity officers: identifying individual directors.
Continuing / discontinued operations: identifying specific discontinued operations.
Associates: identifying specific associates.
Operating segments: identifying specific operating segments.
Related parties: identifying specific related parties of various types.
Business combinations: identifying specific business combinations.
Post-employment benefit plans: identifying specific plans.
Share-based payment arrangements: identifying specific arrangements.
Share classes: identifying specific classes.

Generic dimension tags are an important means of achieving full tagging while avoiding any need forcompany-specific extensions.

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Company reporting in the UK – an XBRL success story

10.5 Groupings
A ‘grouping’ contains tags which describe related aspects of a piece of information and are expected
to be used in combination. The tags may be repeated in a report to handle multiple occurrences of thetype of information they cover.
Typically, groupings cover narrowly defined, detailed information. They frequently will include a
combination of descriptive text tags and monetary tags. An example is the grouping for specific bankloans shown below. This may be used multiple times to handle different loans.

The heading item marked as a ‘grouping’ is purely a container and is not itself used in tagging.
Tags in groupings operate like other line item tags. Technically, they are attached to a special ‘typed
dimension’ which enables the fact that they are being used in combination to be recognised by softwareand also enables them to be repeated, when necessary. Historically, features called ‘tuples’ have beenused in XBRL to group together related information, but these have been replaced in the latest UK
taxonomies by groupings using typed dimensions, since the latter offer greater consistency and usability.
Groupings offer significant benefits in enabling the easy tagging of detailed, company-specificinformation. The latest UK accounts taxonomies contain 23 groupings. These cover a broad range ofsubjects, including information on individual share issues, specific deferred tax assets, director loans andguarantees, material individual assets and other detailed reporting required by accounting standards.

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Company reporting in the UK – an XBRL success story

11. Other taxonomy features
11.1 Guidance information
The taxonomies contain a range of information to help users apply them correctly.
a.

Guidance tags
Guidance tags appear in the presentation view. They provide guidance on how sets of tags
should be used, reminders on the use of dimensions and similar help. They contain the word
[guidance] at the end of their labels and have a ‘guidance item’ data type. (The latter enables
easy identification by software and special display if required.)
Guidance items cannot give full explanations on taxonomy use – that is the role of taxonomy
documentation – but they provide prompts and reminders of key points to users. The figure
below shows guidance tags that provide reminders on the use of dimensions.

Other guidance tags give reminders on the method or scope of tagging:b.

Cross-reference tags
Cross-reference tags appear in the presentation view and point to sections where related
information may be found, helping users navigate through taxonomies. Taxonomy software
is expected to use hyperlinks to enable users to move at a single click between the tags andrelated information. Examples of some cross-reference tags are shown below.

All cross-reference tags are connected to the section at which they point by special links placedin the taxonomies definition linkbase. These ‘custom arcs’ enable software developers to create
hyperlinking in taxonomy displays.
As explained in section 7 on the key features of the taxonomies, ‘documentation fields’ are attachedto some individual tags to give additional guidance on their use. Line item tags carry accounting
references to help confirm their meaning. Documents accompanying the taxonomies explain how
they should be used by preparers and handled by software developers. They also set out consistency
checks which can be used by software to test the completeness and accuracy of tagging.

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Company reporting in the UK – an XBRL success story

11.2 Text tagging
The main purposes of tags for textual information in the UK taxonomies are to identify:

•
•
•
•

Important data, such as names of entities.
Significant descriptive items, such as specific accounting policies.
Important statements, for example on the status of the company and its accounts.
Supplementary commentary by the entity on some disclosures.

This tagging is intended to confirm the presence of and make it easy to find significant textual information.
It is not intended to cover very large slabs of textual reports, such as business reviews, which can best
be read in Inline XBRL in the form intended by the company.
Text tags are generally designed to cover items of textual information in full rather than fragmentsof text which do not make sense when seen in isolation. For example, a single text tag exists to cover a
description of impairment losses recognised or reversed in PPE. The taxonomies do not include separate
tags for descriptions of events leading to impairment, how recoverable amounts are determined,
assumptions lying behind estimates and so forth.
This approach ensures tagged text is immediately comprehensible and useful, as well as avoiding
unnecessary tagging effort by preparers.
Inline XBRL allows separate portions of text, for example before and after a financial table, to becovered by a single text tag. This helps to simplify the tagging of text.
Supplementary commentary in primary statements or notes is covered in the taxonomies by text tagslabelled as ‘free-text comment’ tags. These enable such comments to be captured easily in XBRL.
The labels of text tags follow standard conventions. For example, tags for descriptive information begin‘Description of . . . ’. These conventions help text tags to be easily recognised and understood.

11.3 Technical featuresa.

Fixed value tags
Some tags are intended to represent data which can only take a set of predefined values. The
UK taxonomies handle these through the use of ‘fixed value’ tags. These take their value throughthe dimension tags to which they are attached. The tags themselves are defined as ‘empty’ andhave a special ‘fixedItemType’ datatype. The dimension tags represent all possible values which
they may take.
For example, the ‘Country of formation or incorporation’ tag is attached to the countries
dimension, providing a predefined set of countries for preparers to use. Similarly, the ‘Legal
form of entity’ tag is attached to a legal form of entity dimension containing tags representing
all allowable types of entity.
This provides an easy and reliable way to ensure such tags are only used with correct values
which can be recognised by software.

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Company reporting in the UK – an XBRL success storyb.

Balance attribute and cash flow data
Almost all monetary item tags in the taxonomies carry a balance attribute of debit or credit. This
aids developers in setting up calculation rules in software. However, the application of debit andcredit to cash flow data is not strictly appropriate from an accounting perspective and can leadto calculation anomalies. The UK taxonomies have thus introduced a special feature to identify
cash flow tags and to indicate that a balance attribute of debit on these items means a cash
inflow and credit means a cash outflow.
This is achieved through special links or ‘custom arcs’ in the definition linkbase. All cash inflow
debit items are attached to an inflow arc and all credit items are attached to an outflow arc.
This provides a more rigorous definition from an accounting point of view and helps software to
overcome potential calculation anomalies.

The UK taxonomies include a number of other features to support tagging and enable correct
processing by software. For example, technical features include datatypes to identify heading items,
cross-reference items and the like.
These are described in full in the Tagging Guide and Developer Guide to the taxonomies, available
on the UK Financial Reporting Council website at https://xbrl.frc.org.uk/.

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12. Taxonomy structure, coverage and development
12.1 Structure and coverage
The UK accounts taxonomies principally reflect the requirements of commercial and industrial
companies, but include sections with additional tags for banking and finance, investment funds andthe extractive industries, mining, oil and gas. Extensions are planned for some other industry sectors.
As explained in section 3.3 on the taxonomies and UK accounting regulations, the taxonomies are
structured around a common financial reporting core taxonomy which covers accounting concepts
that derive from the main UK accounting standards.
The taxonomies also include common components covering standard information which may appear
in financial reports. The components comprise:•	Basic information on the entity and the financial statement itself, together with tags for standard
information such as countries and regions. This is termed the ‘Common data’ component.

•••

Directors’ report.
Audit report.
Accountant’s report. (This is for unaudited companies.)

The components are built as separate taxonomy modules, so that they can be used flexibly in future
taxonomy developments.
The basic structure of the main UK accounts taxonomies is shown conceptually in the diagram below.

The FRS 101, FRS 102 and Full IFRS taxonomy components are principally concerned with tailoringand presenting the information contained in the core taxonomy to meet the needs of each standard.
Other taxonomies, particularly for other industry sectors, can build on the same base, importing theunderlying components as required. They may add tags, modify dimensional structures and create
presentation views to suit the sector concerned.

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Company reporting in the UK – an XBRL success story

UK taxonomies do not include ‘calculation’ linkbases to model summations. The UK view is that theselinkbases, which are incapable of representing dimensional information, are not useful.

12.2 Future developments
The FRC is cooperating with other agencies and industry bodies to create taxonomy extensions for
sectors which follow special regulations or practices and whose accounts cannot easily be covered by
the existing taxonomies. It is planning extensions for insurance and smaller companies and is working
with the Charity Commission on an extension for charities accounts.
It plans to update existing taxonomies in the light of developments in accounting standards andexperience in use.
HMRC is separately responsible for two other taxonomies used in the UK for tax reporting. One
covers basic information relating to corporation tax. The other handles the ‘detailed profit and loss’
report, which contains an in-depth breakdown of certain income and expenses. Company filings to
HMRC contain these tax reports as well as accounts.
These HMRC taxonomies follow identical design principles to those used for the accounts
taxonomies. As described below, UK bodies coordinate closely on taxonomy development and use.

12.3 Development process
The project led by the FRC to develop the latest UK accounts taxonomies was a substantial one.
After an initial project planning stage, work on the new taxonomies began in March 2013. They werereleased for public review in May 2014. After revision in light of comments, the final versions wereformally published in September 2014. The project was completed on schedule and within budget.
The development team consisted of a development manager, who was experienced in XBRL andhandled the building of the taxonomies, and accounting specialists seconded from accounting firmsand HMRC. The FRC provided overall project management.
XBRL development at the FRC is overseen by a governance committee which includes representatives
from HMRC, Companies House, the Department of Business (the government ministry in charge ofbusiness affairs), the Institute of Chartered Accountants in England and Wales (ICAEW), a number oflarge accountancy firms and representatives of XBRL UK and XBRL Ireland. This committee sets strategy,
consulting with other agencies when necessary.
A technical committee made up of representatives of accountancy firms, software developers, HMRC
and other bodies monitors the detailed development of taxonomy content and design. Final taxonomy
approval rests with the FRC.
Taxonomies are published in draft and final forms via CoreFiling’s Yeti system which enables them to
be viewed on the internet as well as providing means of gathering comments from reviewers.
XBRL UK, the UK jurisdiction of XBRL International, provides general support for development and useof XBRL in the UK. Bringing together accounting firms, software companies, government departments
and other agencies, it supplies a forum for preparers and consumers of financial information to discussXBRL implementation and plans for its expansion. It helps to foster effective coordination on XBRL in
the UK.

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Company reporting in the UK – an XBRL success story

GLOSSARY

April 2015

Analysis items

Analysis items are line item tags which are designed for use withentries in accounts for which no specific tag exists. Each analysis
item tag is specific to the section in which it appears and may bereused multiple times to tag different entries. See section 10.2 formore information.

Datatypes

Taxonomy tags are assigned a ‘data type’ to identify their meaning
and role and to assist in processing XBRL data.

Definition linkbase

The definition linkbase is used to establish various relationships
between tags in a taxonomy. Its principal function in the UK
taxonomies is to define the structure and use of dimensions (seeother glossary entry), although it also sets other relationships.

Dimensions anddimension tags

Taxonomy dimensions represent the different forms in which financial
data may be reported. Each dimension contains a number ofindividual ‘dimension tags’ to identify the specific breakdowns that
may arise. See section 9 for a fuller explanation.

Extension taxonomy

An extension taxonomy modifies another taxonomy by adding tags,
providing alternative presentation views or other changes. Extensions
must not alter the definition of tags in the base taxonomy. The filingof XBRL reports in the UK is not expected to require companyspecific extension taxonomies.

Financial Reporting
Council

The Financial Reporting Council (FRC) is the UK’s independent
regulator which sets standards for corporate reporting, audit andactuarial practice and which monitors and enforces accounting andauditing standards.

Fixed value tags

Fixed value tags represent data which can only take a set ofpredefined values. These take their value through the dimension
tags to which they are attached. The tags themselves are defined as‘empty’ and have a special ‘fixedItemType’ datatype. The dimension
tags represent all possible values which they may take. See section
11.3 for more information.

FRS 101 and FRS 102

Accounting standards for the UK and Ireland published by the
Financial Reporting Council.

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Company reporting in the UK – an XBRL success story

April 2015

Generic dimension
tags

Generic dimension tags represent classes of information where theprecise name of each member of the class is not known in advance.
Examples include individual directors, individual subsidiaries andthe like. A generic dimension tag consists of the name of theclass followed by a number to indicate the individual tag. Genericdimensions are tied to name or description line item tags which
identify the use of each generic tag. See section 10.4 for more
information.

Grouping

A grouping is used to contain tags which (a) describe related aspectsof a particular piece of information and which are expected to be
used in combination and (b) may be used repetitively in an XBRL
report. See section 10.5 for a fuller explanation.

IFRS

The international accounting regulations published by theInternational Accounting Standards Board (IASB) under which UK
publicly quoted companies report.

Inline XBRL or iXBRLAll XBRL reports in the UK are in Inline XBRL format. This provides ahuman-readable version of a report based on HTML, the languageof the web, with XBRL tags hidden from view in the underlying file. It
provides a powerful solution to the presentation of XBRL data andoffers a range of other benefits. Also known as iXBRL.

Instance document

A file of raw XBRL data. This will consist of facts being represented
in XBRL together with computer-readable XBRL tags and otherrelated XBRL information. It is intended for consumption by computer
software not human readers. It does not contain any presentational
structure.

Label

A label is the human-readable description on an XBRL tag, which
provides its main definition. As far as possible, they uniquely identify
the tag concerned.

Line item tags

Tags which represent ordinary accounting concepts. These are alltags apart from (a) dimension tags (see other glossary entry) and (b)special tags such as headings, guidance items and the like whichcannot directly be used for tagging. Line item tags are shown in fullin the presentation linkbase (see other glossary entry).

Non-standard
dimension tags

Non-standard dimension tags are included in some dimensions tocover untypical classes or breakdowns which cannot be defined inadvance. They fulfil a similar role within dimensions to that handled
by analysis items for line item tags. See section 10.3 for more
information.

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April 2015

Notes to the accounts

Detailed disclosures underlying the primary financial statements.
Known as ‘footnotes’ in some countries.

Presentation viewor linkbase

A user’s basic view of the tags in a taxonomy is defined in thepresentation linkbase. The linkbase can set both the structure andorder of tags.

Tag

An XBRL tag is the computer-readable identifier attached to an itemof business data.

Tagging

The application of XBRL tags to a report as part of the processof creating an iXBRL report. (See other glossary entries for ‘tags’and ‘iXBRL’.) Tags are applied through software. This may be done
automatically or manually, depending on the nature of the reportand software used.

Taxonomy

Taxonomies are the dictionaries of the XBRL language, containing
the computer-readable tags used to identify specific financial andbusiness data items.

Typed dimension

A special type of dimension which does not contain a set of specific,
predefined dimension tags, but is defined by some general property.
The typed dimensions in the UK taxonomies are used with analysis
item tags and groupings (see other glossary entries). These typed
dimensions are defined as containing dimension tags represented
by positive integers. They effectively provide ‘anonymous’ dimension
tags which enable the line items tags attached to them to be reused
any number of times by changing the integer for each occurrence.
See the guidance documents published with the taxonomies formore information.

32

Company reporting in the UK – an XBRL success story

THE XBRL UK JURISDICTIONXBRL UK is a long-standing jurisdiction of the XBRL International consortium (XII).
Dedicated to advancing the use of XBRL in the United Kingdom, XBRL UK’s main activities include:• Promoting the XBRL standard through marketing and educational information.
• Providing technical and other support to those adopting XBRL.
• Representing UK interests within XBRL International.
• Providing access to European markets and standards-setting working groups through XBRL Europe.
XBRL UK is facilitated by the Institute of Chartered Accountants in England and Wales (ICAEW).
Members include a range of public agencies, accountancy and technical specialists, and software
suppliers.
The UK jurisdiction has worked closely with HMRC and Companies House to develop their respective
XBRL filing projects, providing public and technical feedback and advice at both design andimplementation phases.
XBRL UK is most closely identified with the development of the Inline XBRL standard which was developedby jurisdiction members, under the aegis of the XII Rendering Working Group, in order to resolve
technical and market-acceptance issues around the HMRC corporation tax programme. The iXBRL
standard, which has been the most successful single part of the XBRL standard to date, went on to be
adopted by a number of other OECD countries for their own filing programmes.
The UK jurisdiction provides a programme of face-to-face meetings, conferences and roadshows.
The production of this white paper was coordinated by Peter Calvert.

XBRL UK Limited
17 Cosgrove Road,
Old Stratford,
MK19 6AG

info@xbrl.org.uk
www.xbrl.org.uk

April 201533