Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 689	$ (1,337)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	848	890
Accretion of discount on asset retirement obligations	6	5
Impairments of long-lived assets	0	1,525
Exploration and abandonments, including dry holes	29	47
Non-cash stock-based compensation expense	43	43
Deferred income taxes	392	(768)
(Gain) loss on disposition of assets, net	(667)	(109)
(Gain) loss on derivatives	(289)	176
Net settlements received from (paid on) derivatives	126	582
Loss on extinguishment of debt	66	28
Other non-cash items	1	10
Changes in operating assets and liabilities, net of acquisitions and dispositions:
Accounts receivable	(61)	61
Prepaid costs and other	(1)	7
Inventory	(1)	2
Accounts payable	7	9
Revenue payable	5	(57)
Other current liabilities	(8)	(95)
Net cash provided by operating activities	1,185	1,019
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures on oil and natural gas properties	(1,958)	(927)
Additions to property, equipment and other assets	(34)	(20)
Proceeds from the disposition of assets	803	296
Direct transaction costs for disposition of assets	(18)	0
Funds held in escrow	0	(81)
Contributions to equity method investments	0	(51)
Net cash used in investing activities	(1,207)	(783)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of debt	2,267	0
Payments of debt	(2,255)	(600)
Debt extinguishment costs	(63)	(21)
Excess tax benefit (deficiency) from stock-based compensation	0	(1)
Net proceeds from issuance of common stock	0	1,327
Payments for loan costs	(25)	0
Purchase of treasury stock	(23)	(11)
Increase (decrease) in bank overdrafts	68	0
Net cash provided by (used in) financing activities	(31)	694
Net increase (decrease) in cash and cash equivalents	(53)	930
Cash and cash equivalents at beginning of period	53	229
Cash and cash equivalents at end of period	0	1,159
NON-CASH INVESTING AND FINANCING ACTIVITIES:
Issuance of common stock for business combinations	$ 291	$ 231