Consolidated Statements of Income and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net Operating Revenues
Crude Oil and Condensate	$ 3,838,284	$ 1,998,771	$ 1,089,711
Natural Gas Liquids	779,364	462,345	258,799
Natural Gas	2,240,540	2,420,099	2,050,963
Gains on Mark-to-Market Commodity Derivative Contracts	(626,053)	(61,912)	(431,757)
Gathering, Processing and Marketing	2,115,792	909,680	407,116
Gains on Asset Dispositions, Net	492,909	223,538	535,436
Other, Net	33,173	23,551	13,177
Total	10,126,115	6,099,896	4,786,959
Operating Expenses
Lease and Well	941,954	698,430	579,290
Transportation Costs	430,322	385,189	283,329
Gathering and Processing Costs	80,727	66,758	57,632
Exploration Costs	171,658	187,381	169,592
Dry Hole Costs	53,230	72,486	51,243
Impairments	1,031,037	742,647	305,832
Marketing Costs	2,072,137	884,212	397,375
Depreciation, Depletion and Amortization	2,516,381	1,941,926	1,549,188
General and Administrative	304,811	280,474	248,274
Taxes Other Than Income	410,549	317,074	174,363
Total	8,012,806	5,576,577	3,816,118
Operating Income	2,113,309	523,319	970,841
Other Income, Net	6,853	14,243	2,071
Income Before Interest Expense and Income Taxes	2,120,162	537,562	972,912
Interest Expense
Incurred	268,104	205,886	155,820
Capitalized	(57,741)	(76,300)	(54,919)
Interest Expense, Net	210,363	129,586	100,901
Income Before Income Taxes	1,909,799	407,976	872,011
Income Tax Provision	818,676	247,322	325,384
Net Income	1,091,123	160,654	546,627
Net Income Per Share Available to Common Stockholders
Basic	$ 4.15	$ 0.64	$ 2.20
Diluted	$ 4.10	$ 0.63	$ 2.17
Dividends Declared per Common Share	$ 0.64	$ 0.62	$ 0.58
Average Number of Common Shares
Basic	262,735	250,876	248,996
Diluted	266,268	254,500	251,884
Quarterly cash dividend	$ 0.64	$ 0.62	$ 0.58
Comprehensive Income
Net Income	1,091,123	160,654	546,627
Other Comprehensive Income (Loss)
Foreign Currency Translation Adjustments	(32,597)	96,179	308,286
Foreign Currency Swap Transaction	(1,571)	4,447	6,336
Income Tax Related to Foreign Currency Swap Transaction	404	(1,203)	(1,519)
Interest Rate Swap Transaction	(5,223)	1,843	0
Income Tax Related to Interest Rate Swap Transaction	1,878	(664)	0
Other	(1,216)	(251)	(1,170)
Comprehensive Income	$ 1,052,798	$ 261,005	$ 858,560