Asset Retirement Obligations (Tables)

3 Months Ended

Mar. 31, 2019

Asset Retirement Obligation [Abstract]

Schedule of asset retirement obligations

Asset retirement obligations activity is as follows:

	Three Months Ended March 31,
	2019			2018
	(in millions)
Beginning asset retirement obligations	$	183		$	271
New wells placed on production	—			1
Changes in estimates	—			2
Obligations reclassified to liabilities held for sale	—			(6		)
Liabilities settled	(6		)	(9		)
Accretion of discount	3			4
Ending asset retirement obligations	$	180		$	263