Consolidated Statement of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income (loss)	$ 147	$ (1,184)	$ 539
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation, depletion and amortization	930	955	767
Deferred Income Tax Expense (Benefit), Continuing and Discontinuing Operations	143	1	208
Stock-based compensation	43	35	29
Commodity derivative income	97	(120)	(195)
Cash receipts on derivative settlements, net	60	135	195
Ceiling test impairment	0	1,488	0
Other non-cash charges	14	19	6
Changes in operating assets and liabilities:
(Increase) decrease in accounts receivable	(62)	(70)	(24)
(Increase) decrease in inventories	(11)	(35)	(16)
(Increase) decrease in other current assets	12	5	(12)
(Increase) decrease in other assets	6	7	(7)
Increase (decrease) in accounts payable and accrued liabilities	74	(77)	120
Increase (decrease) in advances from joint owners	(1)	(14)	(6)
Increase (decrease) in other liabilities	(7)	2	(15)
Net cash provided by operating activities	1,445	1,147	1,589
Cash flows from investing activities:
Additions to oil and gas properties	(1,987)	(1,758)	(2,311)
Acquisitions of oil and gas properties	(72)	(9)	(304)
Proceeds from sales of oil and gas properties	36	630	406
Additions to furniture, fixtures and equipment	(36)	(22)	(29)
Redemptions of investments	1	0	2
Net cash used in investing activities	(2,058)	(1,159)	(2,236)
Cash flows from financing activities:
Proceeds from borrowings under credit arrangements	3,263	2,844	3,958
Repayments of borrowings under credit arrangements	(2,614)	(2,930)	(4,007)
Proceeds from issuance of senior notes	0	1,000	750
Debt issue costs	(4)	(10)	(16)
Repayment of senior subordinated notes	0	(875)	0
Proceeds from issuances of common stock	1	2	13
Payments for Repurchase of Preferred Stock and Preference Stock	(20)	0	0
Purchases of treasury stock, net	(6)	(7)	(14)
Net cash provided by (used in) financing activities	620	24	684
Increase (decrease) in cash and cash equivalents	7	12	37
Cash and cash equivalents, beginning of period	88	76	39
Cash and cash equivalents, end of period	$ 95	$ 88	$ 76