Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash Flows from Operating Activities
Net Income	$ 324,009	$ 133,973
Items Not Requiring (Providing) Cash
Depreciation, Depletion and Amortization	748,743	568,226
Impairments	133,147	89,328
Stock-Based Compensation Expenses	28,338	27,430
Deferred Income Taxes	110,148	31,290
Gains on Asset Dispositions, Net	(67,468)	(71,742)
Other, Net	446	2,523
Dry Hole Costs	0	22,951
Mark-to-Market Commodity Derivative Contracts
Total Gains (Losses)	134,208	(66,746)
Realized Gains	133,601	24,937
Excess Tax Benefits from Stock-Based Compensation	(16,651)	0
Other, Net	3,352	6,219
Changes in Components of Working Capital and Other Assets and Liabilities
Accounts Receivable	(89,948)	(113,855)
Inventories	10,208	(67,733)
Accounts Payable	236,625	165,497
Accrued Taxes Payable	(5,163)	79,748
Other Assets	(108,840)	(18,656)
Other Liabilities	(5,059)	8,621
Changes in Components of Working Capital Associated with Investing and Financing Activities	(223,675)	1,985
Net Cash Provided by Operating Activities	1,077,605	957,488
Investing Cash Flows
Additions to Oil and Gas Properties	(1,878,813)	(1,527,854)
Additions to Other Property, Plant and Equipment	(170,704)	(159,794)
Proceeds from Sales of Assets	450,110	260,107
Changes in Components of Working Capital Associated with Investing Activities	224,087	(206)
Net Cash Used in Investing Activities	(1,375,320)	(1,427,747)
Financing Cash Flows
Common Stock Sold	0	1,388,211
Dividends Paid	(43,250)	(39,003)
Excess Tax Benefits from Stock-Based Compensation	16,651	0
Treasury Stock Purchased	(20,072)	(14,981)
Proceeds from Stock Options Exercised	20,198	17,363
Other, Net	(412)	(1,779)
Net Cash (Used in) Provided by Financing Activities	(26,885)	1,349,811
Effect of Exchange Rate Changes on Cash	2,938	(120)
(Decrease) Increase in Cash and Cash Equivalents	(321,662)	879,432
Cash and Cash Equivalents at Beginning of Period	615,726	788,853
Cash and Cash Equivalents at End of Year	$ 294,064	$ 1,668,285