Property, Plant and Equipment (Tables)

9 Months Ended

Sep. 30, 2015

Oil and Gas Exploration and Production Industries Disclosures [Abstract]

Schedule of changes in net asset retirement liability

The net asset retirement liability as of September 30, 2015 on our consolidated balance sheet in other current and non-current liabilities and the changes in the net liability from January 1 through September 30, 2015 were as follows:

	2015
	(in millions)
Net asset retirement liability at January 1	$	42
Liabilities incurred	4
Liabilities settled	(2		)
Accretion expense	2
Changes in estimate	(6		)
Net asset retirement liability at September 30	$	40