CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities
Net (loss) income	$ (17)	$ 97
Adjustments to reconcile net (loss) income to net cash provided by operating activities
Depreciation, depletion and amortization	737	642
Impairment charges	0	19
Deferred income tax (benefit) expense	(14)	60
Loss on extinguishment of debt	41	17
Share-based compensation expense	14	12
Non-cash portion of exploration expense	10	15
Amortization of debt issuance costs	14	16
Other	0	1
Asset and liability changes
Accounts receivable	45	5
Accounts payable	(56)	(7)
Derivative instruments	196	(16)
Accrued interest	49	52
Other asset changes	21	4
Other liability changes	(1)	(11)
Net cash provided by operating activities	1,039	906
Cash flows from investing activities
Capital expenditures	(1,203)	(1,521)
Proceeds from the sale of assets, net of cash transferred	0	126
Cash paid for acquisitions, net of cash acquired	(114)	(154)
Net cash used in investing activities	(1,317)	(1,549)
Cash flows from financing activities
Proceeds from issuance of long-term debt	1,777	1,835
Repayments of long-term debt	(1,473)	(1,895)
Proceeds from issuance of stock	0	669
Debt issuance costs	(19)	0
Other	(1)	0
Net cash provided by financing activities	284	609
Change in cash and cash equivalents	6	(34)
Cash and cash equivalents
Beginning of period	22	51
End of period	$ 28	$ 17