Consolidated Statements of Operations (unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues
Oil, Gas and NGL Sales	$ 1,338	$ 1,112	$ 2,665	$ 2,196
Income from Equity Method Investees	45	37	97	96
Total Revenues	1,383	1,149	2,762	2,292
Costs and Expenses
Production Expense	248	210	481	398
Exploration Expense	59	90	133	151
Depreciation, Depletion and Amortization	413	368	837	734
General and Administrative	127	104	266	216
(Gain) Loss on Divestitures	(44)	4	(42)	(12)
Asset Impairments	34	0	131	0
Other Operating Expense, Net	17	12	23	20
Total	854	788	1,829	1,507
Operating Income	529	361	933	785
Other (Income) Expense
(Gain) Loss on Commodity Derivative Instruments	236	(161)	311	(89)
Interest, Net of Amount Capitalized	52	33	99	58
Other Non-Operating Expense, Net	8	3	13	12
Total	296	(125)	423	(19)
Income from Continuing Operations Before Income Taxes	233	486	510	804
Income Tax Provision	41	128	118	214
Income from Continuing Operations	192	358	392	590
Discontinued Operations, Net of Tax	0	19	0	49
Net Income	$ 192	$ 377	$ 392	$ 639
Earnings Per Share, Basic [Abstract]
Income from Continuing Operations (in dollars per share)	$ 0.53	$ 1.00	$ 1.09	$ 1.64
Discontinued Operations, Net of Tax (in dollars per share)	$ 0.00	$ 0.05	$ 0.00	$ 0.14
Net Income (in dollars per share)	$ 0.53	$ 1.05	$ 1.09	$ 1.78
Earnings Per Share, Diluted [Abstract]
Income from Continuing Operations (in dollars per share)	$ 0.52	$ 0.99	$ 1.07	$ 1.63
Discontinued Operations, Net of Tax (in dollars per share)	$ 0.00	$ 0.05	$ 0.00	$ 0.13
Net Income (in dollars per share)	$ 0.52	$ 1.04	$ 1.07	$ 1.76
Weighted Average Number of Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding, Basic (in shares)	361	359	361	358
Weighted Average Number of Shares Outstanding, Diluted (in shares)	366	363	365	362