Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash Flows from Operating Activities
Net Income	$ 1,091,123	$ 160,654	$ 546,627
Items Not Requiring (Providing) Cash
Depreciation, Depletion and Amortization	2,516,381	1,941,926	1,549,188
Impairments	1,031,037	742,647	305,832
Stock-Based Compensation Expenses	128,345	107,378	95,180
Deferred Income Taxes	499,300	76,245	174,392
Gains on Asset Dispositions, Net	(492,909)	(223,538)	(535,436)
Other, Net	15,139	(468)	6,761
Dry Hole Costs	53,230	72,486	51,243
Mark-to-Market Commodity Derivative Contracts
Total Gains	(626,053)	(61,912)	(431,757)
Realized Gains	180,701	7,033	1,277,584
Excess Tax Benefits from Stock-Based Compensation	0	0	(76,134)
Other, Net	26,454	17,273	18,862
Changes in Components of Working Capital and Other Assets and Liabilities
Accounts Receivable	(339,780)	(339,126)	(47,818)
Inventories	(176,623)	(171,971)	(50,146)
Accounts Payable	351,087	654,688	(153,565)
Other Assets	(23,625)	(32,169)	(5,515)
Other Liabilities	14,986	19,342	(12,305)
Changes in Components of Working Capital Associated with Investing and Financing Activities	237,028	(208,968)	118,517
Net Cash Provided by Operating Activities	4,578,410	2,708,602	2,922,439
Investing Cash Flows
Additions to Oil and Gas Properties	(6,294,397)	(5,210,612)	(3,176,783)
Additions to Other Property, Plant and Equipment	(656,415)	(370,770)	(326,226)
Acquisition of Galveston LNG Inc.	0	(210,000)	0
Proceeds from Sales of Assets	1,433,137	672,593	212,000
Changes in Components of Working Capital Associated with Investing Activities	(237,267)	208,933	(118,221)
Other, Net	0	7,082	(5,321)
Net Cash Used in Investing Activities	(5,754,942)	(4,902,774)	(3,414,551)
Financing Cash Flows
Common Stock Sold	1,388,265	0	0
Long-Term Debt Borrowings	0	2,478,659	900,000
Long-Term Debt Repayments	(220,000)	(37,000)	0
Dividends Paid	(167,169)	(153,240)	(142,260)
Excess Tax Benefits from Stock-Based Compensation	0	0	76,134
Treasury Stock Purchased	(23,922)	(11,295)	(10,986)
Proceeds from Stock Options Exercised and Employee Stock Purchase Plan	35,913	34,560	20,465
Debt Issuance Costs	(4,787)	(8,300)	(8,895)
Other, Net	239	35	(296)
Net Cash Provided by Financing Activities	1,008,539	2,303,419	834,162
Effect of Exchange Rate Changes on Cash	(5,134)	(6,145)	12,390
(Decrease) Increase in Cash and Cash Equivalents	(173,127)	103,102	354,440
Cash and Cash Equivalents at Beginning of Year	788,853	685,751	331,311
Cash and Cash Equivalents at End of Year	$ 615,726	$ 788,853	$ 685,751