Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 802	$ (1,286)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	564	591
Accretion of discount on asset retirement obligations	4	3
Impairments of long-lived assets	0	1,525
Exploration and abandonments, including dry holes	24	39
Non-cash stock-based compensation expense	26	28
Deferred income taxes	454	(740)
(Gain) loss on disposition of assets, net	(654)	(110)
(Gain) loss on derivatives	(495)	217
Net settlements received from (paid on) derivatives	96	427
Loss on extinguishment of debt	1	0
Other non-cash items	1	8
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accounts receivable	(24)	60
Prepaid costs and other	(3)	(9)
Inventory	1	3
Accounts payable	(2)	7
Revenue payable	(2)	(59)
Other current liabilities	12	(28)
Net cash provided by (used in) operating activities	805	676
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures on oil and natural gas properties	(863)	(651)
Additions to property, equipment and other assets	(30)	(16)
Proceeds from the disposition of assets	803	294
Direct transaction costs for disposition of assets	(18)	0
Funds held in escrow	(60)	0
Contributions to equity method investments	0	(39)
Net cash provided by (used in) investing activities	(168)	(412)
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)
Payments for loan costs	(7)	0
Purchase of treasury stock	(21)	(11)
Net cash provided by (used in) financing activities	(28)	(12)
Net increase (decrease) in cash and cash equivalents	609	252
Cash and cash equivalents at beginning of period	53	229
Cash and cash equivalents at end of period	662	481
NON-CASH INVESTING AND FINANCING ACTIVITIES:
Issuance of common stock for business combinations	$ 291	$ 231