Consolidated Statements of Income and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net Operating Revenues
Crude Oil and Condensate	$ 2,337,742	$ 1,512,168	$ 6,132,574	$ 4,198,753
Natural Gas Liquids	208,190	170,351	556,176	518,684
Natural Gas	396,123	426,728	1,269,604	1,153,433
(Losses) Gains on Mark-to-Market Commodity Derivative Contracts	(293,387)	4,671	(206,853)	327,328
Gathering, Processing and Marketing	872,699	764,385	2,755,069	2,193,290
Gains on Asset Dispositions, Net	8,183	67,376	185,569	248,134
Other, Net	11,846	9,176	45,956	31,203
Total	3,541,396	2,954,855	10,738,095	8,670,825
Operating Expenses
Lease and Well	299,169	253,452	817,057	765,703
Transportation Costs	219,790	164,407	628,538	431,642
Gathering and Processing Costs	31,121	26,223	81,522	72,403
Exploration Costs	39,429	45,953	130,968	136,909
Dry Hole Costs	19,548	1,924	59,260	13,005
Impairments	85,917	62,875	177,432	250,239
Marketing Costs	876,761	755,457	2,746,900	2,155,043
Depreciation, Depletion and Amortization	928,800	825,851	2,685,719	2,383,359
General and Administrative	98,654	92,870	257,246	244,866
Taxes Other Than Income	172,438	120,096	458,566	359,798
Total	2,771,627	2,349,108	8,043,208	6,812,967
Operating Income	769,769	605,747	2,694,887	1,857,858
Other Income, Net	11,168	7,596	5,867	22,902
Income Before Interest Expense and Income Taxes	780,937	613,343	2,700,754	1,880,760
Interest Expense
Interest Expense, Net	59,382	53,154	182,950	154,198
Income Before Income Taxes	721,555	560,189	2,517,804	1,726,562
Income Tax Provision	259,057	204,698	900,889	651,284
Net Income	462,498	355,491	1,616,915	1,075,278
Net Income Per Share
Basic	$ 1.71	$ 1.33	$ 5.99	$ 4.03
Diluted	$ 1.69	$ 1.31	$ 5.93	$ 3.98
Dividends Declared per Common Share	$ 0.1875	$ 0.17	$ 0.5625	$ 0.51
Average Number of Common Shares
Basic	270,471	267,941	269,934	267,136
Diluted	273,576	270,982	272,856	270,328
Comprehensive Income
Net Income	462,498	355,491	1,616,915	1,075,278
Other Comprehensive Income (Loss)
Foreign Currency Translation Adjustments	15,106	50,426	(18,472)	48,262
Foreign Currency Swap Transaction	1,459	1,708	2,498	2,338
Income Tax Related to Foreign Currency Swap Transaction	0	(646)	0	(597)
Interest Rate Swap Transaction	678	(318)	1,999	(682)
Income Tax Related to Interest Rate Swap Transaction	(244)	114	(719)	245
Other	27	29	82	87
Other Comprehensive Income (Loss)	17,026	51,313	(14,612)	49,653
Comprehensive Income	$ 479,524	$ 406,804	$ 1,602,303	$ 1,124,931