Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 650	$ (1,020)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	283	310
Accretion of discount on asset retirement obligations	2	2
Impairments of long-lived assets	0	1,525
Exploration and abandonments, including dry holes	6	21
Non-cash stock-based compensation expense	12	16
Deferred income taxes	363	(584)
(Gain) loss on disposition of assets, net	(654)	(111)
(Gain) loss on derivatives	(286)	(81)
Net settlements received from (paid on) derivatives	28	259
Other non-cash items	1	4
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accounts receivable	(6)	68
Prepaid costs and other	(8)	(5)
Accounts payable	7	8
Revenue payable	8	(44)
Other current liabilities	1	2
Net cash provided by (used in) operating activities	407	370
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures on oil and natural gas properties	(457)	(380)
Additions to property, equipment and other assets	(2)	(9)
Proceeds from the disposition of assets	806	292
Direct transaction costs for disposition of assets	(17)	0
Contributions to equity method investments	0	(25)
Net cash provided by (used in) investing activities	330	(122)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of debt	105	0
Payments of debt	(105)	0
Excess tax benefit (deficiency) from stock-based compensation	0	(1)
Purchase of treasury stock	(19)	(9)
Net cash provided by (used in) financing activities	(19)	(10)
Net increase (decrease) in cash and cash equivalents	718	238
Cash and cash equivalents at beginning of period	53	229
Cash and cash equivalents at end of period	771	467
NON-CASH INVESTING AND FINANCING ACTIVITIES:
Issuance of common stock for business combinations	$ 258	$ 231