Asset Retirement Obligations

12 Months Ended

Dec. 31, 2018

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

9.  Asset Retirement Obligations

The following table describes changes to and maturity of our asset retirement obligations:

	2018			2017
	(In millions)
Balance at January 1	$	801		$	2,128
Liabilities incurred		68			62
Liabilities settled or disposed of		(46	)		(1,464	)
Accretion expense		37			97
Revisions of estimated liabilities		1			(54	)
Foreign currency remeasurement		(4	)		32
Balance at December 31	$	857		$	801
Total Asset Retirement Obligations at December 31:
Current portion of asset retirement obligations	$	116		$	48
Long-term asset retirement obligations		741			753
Total at December 31	$	857		$	801

The liabilities incurred in 2018 include $25 million related to acquired participating interests.  The liabilities settled or disposed of in 2017 primarily relate to the sale of our interests in Norway and Equatorial Guinea.  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 $148 million at December 31, 2018 (2017: $118 million).