CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash Flows From Operating Activities
Net income (loss)	$ (4,556)	$ 924	$ 704
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	1,092	942	787
Impairment of natural gas and oil properties	6,950
Amortization of debt issuance cost	53	10	4
Deferred income taxes	(2,003)	504	497
(Gain) loss on derivatives, net of settlement	155	(130)	(21)
Stock-based compensation	26	18	13
Gain on sale of assets, net	(283)
Other	34	2	1
Change in assets and liabilities:
Accounts receivable	203	(66)	(86)
Inventories	4	1	(6)
Accounts payable	(78)	84	74
Taxes payable	(28)	24	5
Interest payable	9		(1)
Advances from partners			(69)
Other assets and liabilities	2	22	7
Net cash provided by operating activities	1,580	2,335	1,909
Cash Flows From Investing Activities
Capital investments	(1,798)	(2,043)	(2,157)
Acquisitions	(579)	(5,298)	(96)
Proceeds from sale of property and equipment	729	43	18
Transfers to restricted cash			9
Other	10	10	10
Net cash used in investing activities	(1,638)	(7,288)	(2,216)
Cash Flows From Financing Activities
Payments on current portion of long-term debt	(1)	(1)	(1)
Payments on long-term debt	(500)
Payments on short-term debt	(4,500)
Payments on revolving credit facility	(3,024)	(5,179)	(3,148)
Borrowings under revolving credit facility	2,840	5,196	3,430
Payments on commercial paper	(7,988)
Borrowings under commercial paper	7,988
Change in bank drafts outstanding	12	11	(7)
Proceeds from issuance of long-term debt	2,950	500
Proceeds from issuance of short-term debt		4,500
Debt issuance costs	(20)	(56)
Proceeds from exercise of common stock options		12	10
Proceeds from issuance of common stock	669
Proceeds from issuance of mandatory convertible preferred stock	1,673
Preferred stock dividend	(79)
Other			(7)
Net cash provided by financing activities	20	4,983	277
Effect of exchange rate changes on cash			(1)
Increase (decrease) in cash and cash equivalents	(38)	30	(31)
Cash and cash equivalents at beginning of year	53	23	54
Cash and cash equivalents at end of year	$ 15	$ 53	$ 23