Consolidated Statements of Operations (unaudited) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues
Oil, Gas and NGL Sales	$ 1,327	$ 1,083
Income from Equity Method Investees	52	60
Total Revenues	1,379	1,143
Costs and Expenses
Production Expense	232	187
Exploration Expense	74	61
Depreciation, Depletion and Amortization	425	366
General and Administrative	140	112
Asset Impairments	97	0
Other Operating (Income) Expense, Net	7	(8)
Total	975	718
Operating Income	404	425
Other (Income) Expense
Loss on Commodity Derivative Instruments	(75)	(72)
Interest, Net of Amount Capitalized	47	25
Other Non-Operating Expense, Net	5	10
Total	127	107
Income from Continuing Operations Before Income Taxes	277	318
Income Tax Provision	77	86
Income from Continuing Operations	200	232
Discontinued Operations, Net of Tax	0	29
Net Income	$ 200	$ 261
Earnings Per Share, Basic [Abstract]
Income from Continuing Operations (in dollars per share)	$ 0.56	$ 0.65
Discontinued Operations, Net of Tax (in dollars per share)	$ 0.00	$ 0.08
Net Income (in dollars per share)	$ 0.56	$ 0.73
Earnings Per Share, Diluted [Abstract]
Income from Continuing Operations (in dollars per share)	$ 0.55	$ 0.64
Discontinued Operations, Net of Tax (in dollars per share)	$ 0.00	$ 0.08
Net Income (in dollars per share)	$ 0.55	$ 0.72
Weighted Average Number of Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding, Basic (in shares)	360	358
Weighted Average Number of Shares Outstanding, Diluted (in shares)	365	362