Asset Retirement Obligations

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

9.  Asset Retirement Obligations

The following table describes changes to our asset retirement obligations:

	2019			2018
	(In millions)
Balance at January 1	$	857		$	801
Liabilities incurred		72			68
Liabilities settled or disposed of		(75	)		(46	)
Accretion expense		40			37
Revisions of estimated liabilities		129			1
Foreign currency remeasurement		1			(4	)
Balance at December 31	$	1,024		$	857
Total Asset Retirement Obligations at December 31:
Current portion of asset retirement obligations	$	127		$	116
Long-term asset retirement obligations		897			741
Total at December 31	$	1,024		$	857

The liabilities incurred in 2019 primarily relate to operations in Guyana, the U.S. and Malaysia, while liabilities incurred in 2018 primarily relate to operations in the U.S. and UK as well as acquired participating interests.  The liabilities settled or disposed of primarily reflect activity in the Gulf of Mexico and the Bakken in 2019, while activity in 2018 primarily relates to abandonment activity and an asset disposal onshore in the U.S.  The revisions of estimated liabilities in 2019 reflect an acceleration of planned abandonment activity in the Gulf of Mexico and changes in service and equipment rates.

The fair value of sinking fund deposits that are legally restricted for purposes of settling asset retirement obligations, which are reported in non-current Other assets in the Consolidated Balance Sheet, was $178 million at December 31, 2019 (2018: $148 million).