Fair Value Measurements and Disclosures (Details) (USD $) In Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010		Dec. 31, 2010
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	$ 101				$ 101				$ 112
Commodity Derivative Instruments	131				131				62
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	(6)				(6)				(75)
Interest Rate Derivative Instrument	0				0				(63)
Portion of Deferred Compensation Liability Measured at Fair Value	(152)				(152)				(178)
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Financial Statement Captions [Line Items]
Impaired Oil and Gas Properties	0		100		139		100
Quoted Prices in Active Markets (Level 1) [Member]
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	101	[1]			101	[1]			112	[1]
Commodity Derivative Instruments	0	[1]			0	[1]			0	[1]
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	0	[1]			0	[1]			0	[1]
Interest Rate Derivative Instrument	0	[1]			0	[1]			0	[1]
Portion of Deferred Compensation Liability Measured at Fair Value	(152)	[1]			(152)	[1]			(178)	[1]
Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Financial Statement Captions [Line Items]
Impaired Oil and Gas Properties	0		0		0		0
Significant Other Observable Inputs (Level 2) [Member]
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	0	[2]			0	[2]			0	[2]
Commodity Derivative Instruments	174	[2]			174	[2]			106	[2]
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	(49)	[2]			(49)	[2]			(119)	[2]
Interest Rate Derivative Instrument	0	[2]			0	[2]			(63)	[2]
Portion of Deferred Compensation Liability Measured at Fair Value	0	[2]			0	[2]			0	[2]
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Financial Statement Captions [Line Items]
Impaired Oil and Gas Properties	0		0		0		0
Significant Unobservable Inputs (Level 3) [Member]
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	0	[3]			0	[3]			0	[3]
Commodity Derivative Instruments	0	[3]			0	[3]			0	[3]
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	0	[3]			0	[3]			0	[3]
Interest Rate Derivative Instrument	0	[3]			0	[3]			0	[3]
Portion of Deferred Compensation Liability Measured at Fair Value	0	[3]			0	[3]			0	[3]
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Financial Statement Captions [Line Items]
Impaired Oil and Gas Properties	0		48		32		48
Fair Value Inputs Adjustment [Member]
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	0	[4]			0	[4]			0	[4]
Commodity Derivative Instruments	(43)	[4]			(43)	[4]			(44)	[4]
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	43	[4]			43	[4]			44	[4]
Interest Rate Derivative Instrument	0	[4]			0	[4]			0	[4]
Portion of Deferred Compensation Liability Measured at Fair Value	0	[4]			0	[4]			0	[4]
Net Book Value [Member]
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Financial Statement Captions [Line Items]
Impaired Oil and Gas Properties	0	[5]	148	[5]	171	[5]	148	[5]
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Net of Unamortized Discount	3,511	[6]			3,511	[6]			1,977	[6]
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Net of Unamortized Discount	$ 4,031	[6]			$ 4,031	[6]			$ 2,302	[6]

[1] Level 1 measurements are fair value measurements which use quoted market prices (unadjusted) in active markets for identical assets or liabilities. We use Level 1 inputs when available as Level 1 inputs generally provide the most reliable evidence of fair value.

[2] Level 2 measurements are fair value measurements which use inputs, other than quoted prices included within Level 1, which are observable for the asset or liability, either directly or indirectly.

[3] Level 3 measurements are fair value measurements which use unobservable inputs.

[4] Amount represents the impact of master netting agreements that allow us to net cash settle asset and liability positions with the same counterparty.

[5] Amount represents net book value at date of assessment.

[6] Excludes FPSO lease obligation.