Consolidated Statements of Income and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net Operating Revenues
Crude Oil and Condensate	$ 1,376,250	$ 938,518	$ 2,686,585	$ 1,695,880
Natural Gas Liquids	150,023	183,805	348,333	332,532
Natural Gas	359,421	599,993	726,705	1,183,912
Gains on Mark-to-Market Commodity Derivative Contracts	188,449	189,621	322,657	122,875
Gathering, Processing and Marketing	710,748	487,698	1,428,905	883,281
Gains on Asset Dispositions, Net	113,290	163,771	180,758	235,513
Other, Net	11,138	6,844	22,027	13,363
Total	2,909,319	2,570,250	5,715,970	4,467,356
Operating Expenses
Lease and Well	250,756	216,695	512,251	431,784
Transportation Costs	135,393	101,965	267,235	199,598
Gathering and Processing Costs	20,588	17,716	46,180	36,912
Exploration Costs	48,149	41,238	90,956	92,147
Dry Hole Costs	11,081	1,676	11,081	24,627
Impairments	54,217	358,654	187,364	447,982
Marketing Costs	694,118	469,437	1,399,586	854,846
Depreciation, Depletion and Amortization	808,765	602,944	1,557,508	1,171,170
General and Administrative	75,727	67,406	151,996	137,443
Taxes Other Than Income	118,186	104,266	239,702	210,143
Total	2,216,980	1,981,997	4,463,859	3,606,652
Operating Income	692,339	588,253	1,252,111	860,704
Other Income, Net	4,675	6,224	15,306	9,828
Income Before Interest Expense and Income Taxes	697,014	594,477	1,267,417	870,532
Interest Expense, Net	50,775	51,253	101,044	101,586
Income Before Income Taxes	646,239	543,224	1,166,373	768,946
Income Tax Provision	250,461	247,650	446,586	339,399
Net Income	395,778	295,574	719,787	429,547
Net Income Per Share
Basic	$ 1.48	$ 1.11	$ 2.70	$ 1.65
Diluted	$ 1.47	$ 1.10	$ 2.67	$ 1.63
Dividends Declared per Common Share	$ 0.17	$ 0.16	$ 0.34	$ 0.32
Average Number of Common Shares
Basic	266,874	265,830	266,718	259,766
Diluted	269,985	269,332	270,083	263,363
Comprehensive Income
Net Income	395,778	295,574	719,787	429,547
Other Comprehensive Income (Loss)
Foreign Currency Translation Adjustments	(28,689)	11,673	(2,164)	55,515
Foreign Currency Swap	(1,431)	(843)	630	(184)
Income Tax Related to Foreign Currency Swap	576	216	49	52
Interest Rate Swap	231	(5,713)	(364)	(4,109)
Income Tax Related to Interest Rate Swap	(83)	2,055	131	1,477
Other	31	28	58	58
Other Comprehensive Income	(29,365)	7,416	(1,660)	52,809
Comprehensive Income	$ 366,413	$ 302,990	$ 718,127	$ 482,356