Asset Retirement Obligations (Tables)

9 Months Ended

Sep. 30, 2016

Asset Retirement Obligation Disclosure [Abstract]

Summary Of Changes In Asset Retirement Obligations

	Nine Months Ended September 30,
	2016			2015
	(Millions)
Asset retirement obligations as of beginning of period	$	1,414		$	1,399
Liabilities incurred and assumed through acquisitions		18			46
Liabilities settled and divested		(310	)		(48	)
Revision of estimated obligation		70			62
Accretion expense on discounted obligation		58			56
Foreign currency translation adjustment		26			(80	)
Asset retirement obligations as of end of period		1,276			1,435
Less current portion		46			58
Asset retirement obligations, long-term	$	1,230		$	1,377