CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows From Operating Activities:
Net income (loss)	$ (2,643)	$ (4,556)	$ 924
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	436	1,092	942
Impairment of natural gas and oil properties	2,321	6,950
Amortization of debt issuance costs	14	53	10
Deferred income taxes	(22)	(2,003)	504
(Gain) loss on derivatives, net of settlement	373	155	(130)
Stock-based compensation	29	26	18
Gain on sale of assets, net		(283)
Restructuring charges	30
Loss on early extinguishment of debt	51
Other	8	34	2
Change in assets and liabilities:
Accounts receivable	(30)	203	(66)
Accounts payable	(69)	(78)	84
Taxes payable	(5)	(28)	24
Interest payable		9
Other assets and liabilities	5	6	23
Net cash provided by operating activities	498	1,580	2,335
Cash Flows From Investing Activities:
Capital investments	(593)	(1,798)	(2,043)
Acquisitions		(579)	(5,298)
Proceeds from sale of property and equipment	430	729	43
Other	1	10	10
Net cash used in investing activities	(162)	(1,638)	(7,288)
Cash Flows From Financing Activities:
Payments on current portion of long-term debt	(1)	(1)	(1)
Payments on long-term debt	(1,175)	(500)
Payments on short-term debt		(4,500)
Payments on revolving credit facility	(3,268)	(3,024)	(5,179)
Borrowings under revolving credit facility	3,152	2,840	5,196
Payments on commercial paper	(242)	(7,988)
Borrowings under commercial paper	242	7,988
Change in bank drafts outstanding	(20)	12	11
Proceeds from issuance of long-term debt	1,191	2,950	500
Proceeds from issuance of short-term debt			4,500
Debt issuance costs	(17)	(20)	(56)
Proceeds from exercise of common stock options			12
Proceeds from issuance of common stock	1,247	669
Proceeds from issuance of mandatory convertible preferred stock		1,673
Preferred stock dividend	(27)	(79)
Cash paid for tax withholding	(9)
Other	(1)
Net cash provided by financing activities	1,072	20	4,983
Increase (decrease) in cash and cash equivalents	1,408	(38)	30
Cash and cash equivalents at beginning of year	15	53	23
Cash and cash equivalents at end of year	$ 1,423	$ 15	$ 53