Consolidated Statements of Operations (unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues
Oil, Gas and NGL Sales	$ 1,228	$ 1,341	$ 3,893	$ 3,537
Income from Equity Method Investees	41	53	138	150
Total Revenues	1,269	1,394	4,031	3,687
Costs and Expenses
Production Expense	217	221	697	619
Exploration Expense	217	60	350	211
Depreciation, Depletion and Amortization	460	412	1,297	1,146
General and Administrative	132	109	399	324
Gain on Divestitures	(30)	0	(72)	(12)
Asset Impairments	33	63	164	63
Other Operating Expense, Net	10	6	33	27
Total	1,039	871	2,868	2,378
Operating Income	230	523	1,163	1,309
Other (Income) Expense
(Gain) Loss on Commodity Derivative Instruments	(385)	157	(74)	69
Interest, Net of Amount Capitalized	52	46	151	104
Other Non-Operating (Income) Expense, Net	(13)	9	1	21
Total	(346)	212	78	194
Income from Continuing Operations Before Income Taxes	576	311	1,085	1,115
Income Tax Provision	157	116	274	330
Income from Continuing Operations	419	195	811	785
Discontinued Operations, Net of Tax	0	10	0	58
Net Income	$ 419	$ 205	$ 811	$ 843
Earnings Per Share, Basic [Abstract]
Income from Continuing Operations (in dollars per share)	$ 1.16	$ 0.54	$ 2.25	$ 2.19
Discontinued Operations, Net of Tax (in dollars per share)	$ 0.00	$ 0.03	$ 0.00	$ 0.16
Net Income (in dollars per share)	$ 1.16	$ 0.57	$ 2.25	$ 2.35
Earnings Per Share, Diluted [Abstract]
Income from Continuing Operations (in dollars per share)	$ 1.12	$ 0.53	$ 2.21	$ 2.17
Discontinued Operations, Net of Tax (in dollars per share)	$ 0.00	$ 0.03	$ 0.00	$ 0.16
Net Income (in dollars per share)	$ 1.12	$ 0.56	$ 2.21	$ 2.33
Weighted Average Number of Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding, Basic (in shares)	362	359	361	359
Weighted Average Number of Shares Outstanding, Diluted (in shares)	367	363	367	363