Asset Retirement Obligations (Notes)

12 Months Ended

Dec. 31, 2018

Asset Retirement Obligation Disclosure [Abstract]

Asset retirement obligations primarily consist of estimated costs to remove, dismantle and restore land or seabed at the end of oil and gas production operations. Changes in asset retirement obligations for the periods ended December 31 were as follows:



(In millions)	2018			2017
Beginning balance	$	1,483		$	1,652
Incurred liabilities, including acquisitions	21			25
Settled liabilities, including dispositions	(117		)	(50		)
Accretion expense (included in depreciation, depletion and amortization)	70			85
Revisions of estimates	(204		)	(227		)
Held for sale^(a)	(108		)	(2		)
Ending balance^(b)	$	1,145		$	1,483

^(a) In the fourth quarter 2018, we entered into an agreement to sell our working interest in the Droshky field (Gulf of Mexico), including our $98 million asset retirement obligation. This transaction closed during the first quarter of 2019.

^(b) $944 million of the 2018 ending balance relates to our asset retirement obligations in the U.K.

2018


•	Settled liabilities include dispositions, primarily related to the sale of non-core, non-operated conventional properties in the Gulf of Mexico as well as retirements in the U.K.


•	Revisions of estimates were primarily due to the acceleration of U.K. abandonment activities to capture favorable market conditions and lower estimated abandonment costs.


•	Ending balance primarily relates to the U.K. and includes $64 million classified as short-term at December 31, 2018.

2017


•	Settled liabilities include dispositions, primarily related to the sale of certain conventional assets in Oklahoma as well as retirements in the U.K. and the Gulf of Mexico.


•	Revisions of estimates were primarily due to changes in U.K. estimated costs as well as timing of abandonment activities in the U.K.


•	Ending balance primarily relates to the U.K. and includes $55 million classified as short-term at December 31, 2017.