Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2021

Asset Retirement Obligation Disclosure [Abstract]

Changes to Asset Retirement Obligations

The following table describes the changes in our asset retirement obligations for the years ended December 31:

	2021		2020
	(In millions)
Balance at January 1	$	999	$	1,024
Liabilities incurred	229		36
Liabilities settled or disposed of	(207)		(161)
Accretion expense	44		46
Revisions of estimated liabilities	126		52
Foreign currency remeasurement	(1)		2
Balance at December 31	$	1,190	$	999
Total Asset Retirement Obligations at December 31:
Current portion of asset retirement obligations	$	185	$	105
Long-term asset retirement obligations	1,005		894
Total at December 31	$	1,190	$	999