CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
NET INCOME	$ 294	$ 141
ADJUSTMENTS TO RECONCILE NET INCOME (LOSS) TO CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES:
Depreciation, depletion and amortization	286	218
Derivative (gains) losses, net	117	(322)
Cash receipts (payments) on derivative settlements, net	13	(34)
Stock-based compensation	9	11
Net losses on sales of fixed assets	8	0
Gains on investments	(139)	0
Losses on purchases or exchanges of debt	0	6
Other	(36)	(34)
Changes in assets and liabilities	104	113
Net Cash Provided By Operating Activities	656	99
CASH FLOWS FROM INVESTING ACTIVITIES:
Drilling and completion costs	(442)	(433)
Acquisitions of proved and unproved properties	(63)	(95)
Proceeds from divestitures of proved and unproved properties	319	892
Additions to other property and equipment	(3)	(3)
Proceeds from sales of other property and equipment	68	19
Proceeds from sales of investments	74	0
Net Cash Provided By (Used In) Investing Activities	(47)	380
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from revolving credit facility borrowings	2,904	50
Payments on revolving credit facility borrowings	(3,485)	(50)
Cash paid to purchase debt	0	(982)
Cash paid for preferred stock dividends	(23)	(114)
Distributions to noncontrolling interest owners	(2)	(2)
Other	(4)	(14)
Net Cash Used In Financing Activities	(610)	(1,112)
Net decrease in cash and cash equivalents	(1)	(633)
Cash and cash equivalents, beginning of period	5	882
Cash and cash equivalents, end of period	4	249
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid, net of capitalized interest	131	92
Income taxes paid, net of refunds received	0	1
Change in accrued drilling and completion costs [Member]
SUPPLEMENTAL DISCLOSURE OF SIGNIFICANT NON-CASH INVESTING AND FINANCING ACTIVITIES:
Change in non-cash investing and financing activities	103	68
Change in accrued acquisitions of proved and unproved properties [Member]
SUPPLEMENTAL DISCLOSURE OF SIGNIFICANT NON-CASH INVESTING AND FINANCING ACTIVITIES:
Change in non-cash investing and financing activities	0	8
Change in divested proved and unproved properties [Member]
SUPPLEMENTAL DISCLOSURE OF SIGNIFICANT NON-CASH INVESTING AND FINANCING ACTIVITIES:
Change in non-cash investing and financing activities	$ (12)	$ (8)