Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash Flows from Operating Activities
Net Income	$ 494,725	$ 324,009
Items Not Requiring (Providing) Cash
Depreciation, Depletion and Amortization	846,388	748,743
Impairments	53,548	133,147
Stock-Based Compensation Expenses	30,436	28,338
Deferred Income Taxes	200,779	110,148
Gains on Asset Dispositions, Net	(164,233)	(67,468)
Other, Net	8,268	446
Dry Hole Costs	3,962	0
Mark-to-Market Commodity Derivative Contracts
Total (Losses) Gains	104,956	(134,208)
Realized Gains	67,050	133,601
Excess Tax Benefits from Stock-Based Compensation	(11,673)	(16,651)
Other, Net	5,022	3,352
Changes in Components of Working Capital and Other Assets and Liabilities
Accounts Receivable	(236,757)	(89,948)
Inventories	(15,058)	10,208
Accounts Payable	186,065	236,625
Accrued Taxes Payable	9,004	(5,163)
Other Assets	(47,193)	(108,840)
Other Liabilities	(52,933)	(5,059)
Changes in Components of Working Capital Associated with Investing and Financing Activities	(57,421)	(223,675)
Net Cash Provided by Operating Activities	1,424,935	1,077,605
Investing Cash Flows
Additions to Oil and Gas Properties	(1,604,123)	(1,878,813)
Additions to Other Property, Plant and Equipment	(92,201)	(170,704)
Proceeds from Sales of Assets	479,436	450,110
Changes in Components of Working Capital Associated with Investing Activities	57,149	224,087
Net Cash Used in Investing Activities	(1,159,739)	(1,375,320)
Financing Cash Flows
Dividends Paid	(46,220)	(43,250)
Excess Tax Benefits from Stock-Based Compensation	11,673	16,651
Treasury Stock Purchased	(11,024)	(20,072)
Proceeds from Stock Options Exercised and Employee Stock Purchase Plan	8,004	20,198
Repayment of Capital Lease Obligation	(1,427)	0
Other, Net	272	(412)
Net Cash Used in Financing Activities	(38,722)	(26,885)
Effect of Exchange Rate Changes on Cash	5,125	2,938
Increase (Decrease) in Cash and Cash Equivalents	231,599	(321,662)
Cash and Cash Equivalents at Beginning of Period	876,435	615,726
Cash and Cash Equivalents at End of Period	$ 1,108,034	$ 294,064