Asset Retirement Obligations

12 Months Ended

Dec. 31, 2017

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

9.  Asset Retirement Obligations

The following table describes changes to our asset retirement obligations:

	2017			2016
	(In millions)
Balance at January 1	$	2,128		$	2,383
Liabilities incurred		62			42
Liabilities settled or disposed of		(1,464	)		(196	)
Accretion expense		97			117
Revisions of estimated liabilities		(54	)		(230	)
Foreign currency translation		32			12
Balance at December 31		801			2,128
Less: Current Obligations		48			216
Long-term Obligations at end of period	$	753		$	1,912

The liabilities settled or disposed of primarily relate to the sale of our interests in Norway and Equatorial Guinea in 2017.  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 $118 million at December 31, 2017 (2016: $102 million).