Consolidated Statements of Cash Flows (unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash Flows From Operating Activities
Net Income	$ 263	$ 14
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Depreciation, Depletion and Amortization	312	221
Dry Hole Cost	1	22
Deferred Income Taxes	32	11
Dividends (Income) from Equity Method Investees, Net	(29)	(23)
Unrealized (Gain) Loss on Commodity Derivative Instruments	73	303
Other Adjustments for Noncash Items Included in Income	30	36
Changes in Operating Assets and Liabilities
(Increase) in Accounts Receivable	(135)	(9)
(Increase) in Other Current Assets	(5)	(17)
Increase in Accounts Payable	190	28
Increase (Decrease) in Current Income Taxes Payable	5	(71)
(Decrease) in Other Current Liabilities	(26)	(54)
Other Operating Assets and Liabilities, Net	30	23
Net Cash Provided by Operating Activities	741	484
Cash Flows From Investing Activities
Additions to Property, Plant and Equipment	(1,018)	(578)
Additions to Equity Method Investments	(14)	0
Proceeds from Divestitures	0	3
Net Cash Used in Investing Activities	(1,032)	(575)
Cash Flows From Financing Activities
Exercise of Stock Options	27	23
Excess Tax Benefits from Stock-Based Awards	12	8
Dividends Paid, Common Stock	(39)	(32)
Purchase of Treasury Stock	(13)	(16)
Proceeds from Credit Facilities	0	120
Repayment of Credit Facilities	0	(470)
Proceeds from Issuance of Senior Long-Term Debt, Net	0	836
Settlement of Interest Rate Derivative Instrument	0	(40)
Repayment of Capital Lease Obligation	(8)	0
Net Cash Provided By (Used In) Financing Activities	(21)	429
Increase (Decrease) in Cash and Cash Equivalents	(312)	338
Cash and Cash Equivalents at Beginning of Period	1,455	1,081
Cash and Cash Equivalents at End of Period	$ 1,143	$ 1,419