2 .new accounting standards effective january 1 , 2003 , marathon adopted statement of financial accounting standards no .143 201caccounting for asset retirement obligations 201d ( 201csfas no .143 201d ) .this statement requires that the fair value of an asset retirement obligation be recognized in the period in which it is incurred if a reasonable estimate of fair value can be made .the present value of the estimated asset retirement cost is capitalized as part of the carrying amount of the long-lived asset .previous accounting standards used the units-of-production method to match estimated future retirement costs with the revenues generated from the producing assets .in contrast , sfas no .143 requires depreciation of the capitalized asset retirement cost and accretion of the asset retirement obligation over time .the depreciation will generally be determined on a units-of-production basis over the life of the field , while the accretion to be recognized will escalate over the life of the producing assets , typically as production declines .for marathon , asset retirement obligations primarily relate to the abandonment of oil and gas producing facilities .while assets such as refineries , crude oil and product pipelines , and marketing assets have retirement obligations covered by sfas no .143 , certain of those obligations are not recognized since the fair value cannot be estimated due to the uncertainty of the settlement date of the obligation .the transition adjustment related to adopting sfas no .143 on january 1 , 2003 , was recognized as a cumulative effect of a change in accounting principle .the cumulative effect on net income of adopting sfas no .143 was a net favorable effect of $ 4 million , net of tax of $ 4 million .at the time of adoption , total assets increased $ 120 million , and total liabilities increased $ 116 million .the amounts recognized upon adoption are based upon numerous estimates and assumptions , including future retirement costs , future recoverable quantities of oil and gas , future inflation rates and the credit-adjusted risk-free interest rate .changes in asset retirement obligations during the year were : ( in millions ) 2003 pro forma 2002 ( a ) .
[['( in millions )', '2003', 'pro forma2002 ( a )'], ['asset retirement obligations as of january 1', '$ 339', '$ 316'], ['liabilities incurred during 2003 ( b )', '32', '2013'], ['liabilities settled during 2003 ( c )', '-42 ( 42 )', '2013'], ['accretion expense ( included in depreciation depletion and amortization )', '20', '23'], ['revisions of previous estimates', '41', '2013'], ['asset retirement obligations as of december 31', '$ 390', '$ 339']]
( a ) pro forma data as if sfas no .143 had been adopted on january 1 , 2002 .if adopted , income before cumulative effect of changes in accounting principles for 2002 would have been increased by $ 1 million and there would have been no impact on earnings per share .( b ) includes $ 12 million related to the acquisition of khanty mansiysk oil corporation in 2003 .( c ) includes $ 25 million associated with assets sold in 2003 .in the second quarter of 2002 , the financial accounting standards board ( 201cfasb 201d ) issued statement of financial accounting standards no .145 201crescission of fasb statements no .4 , 44 , and 64 , amendment of fasb statement no .13 , and technical corrections 201d ( 201csfas no .145 201d ) .effective january 1 , 2003 , marathon adopted the provisions relating to the classification of the effects of early extinguishment of debt in the consolidated statement of income .as a result , losses of $ 53 million from the early extinguishment of debt in 2002 , which were previously reported as an extraordinary item ( net of tax of $ 20 million ) , have been reclassified into income before income taxes .the adoption of sfas no .145 had no impact on net income for 2002 .effective january 1 , 2003 , marathon adopted statement of financial accounting standards no .146 201caccounting for exit or disposal activities 201d ( 201csfas no .146 201d ) .sfas no .146 is effective for exit or disposal activities that are initiated after december 31 , 2002 .there were no impacts upon the initial adoption of sfas no .146 .effective january 1 , 2003 , marathon adopted the fair value recognition provisions of statement of financial accounting standards no .123 201caccounting for stock-based compensation 201d ( 201csfas no .123 201d ) .statement of financial accounting standards no .148 201caccounting for stock-based compensation 2013 transition and disclosure 201d ( 201csfas no .148 201d ) , an amendment of sfas no .123 , provides alternative methods for the transition of the accounting for stock-based compensation from the intrinsic value method to the fair value method .marathon has applied the fair value method to grants made , modified or settled on or after january 1 , 2003 .the impact on marathon 2019s 2003 net income was not materially different than under previous accounting standards .the fasb issued statement of financial accounting standards no .149 201camendment of statement 133 on derivative instruments and hedging activities 201d on april 30 , 2003 .the statement is effective for derivative contracts entered into or modified after june 30 , 2003 and for hedging relationships designated after june 30 , 2003 .the adoption of this statement did not have an effect on marathon 2019s financial position , cash flows or results of operations .the fasb issued statement of financial accounting standards no .150 201caccounting for certain financial instruments with characteristics of both liabilities and equity 201d on may 30 , 2003 .the adoption of this statement , effective july 1 , 2003 , did not have a material effect on marathon 2019s financial position or results of operations .effective january 1 , 2003 , fasb interpretation no .45 , 201cguarantor 2019s accounting and disclosure requirements for guarantees , including indirect guarantees of indebtedness of others 201d ( 201cfin 45 201d ) , requires the fair-value .

Question: what are total asset retirement obligations as of december 31 2002 and 2003 , in millions?
Answer: 729