Fair Value Measurements and Disclosures (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	$ 108		$ 99
Commodity Derivative Instruments	39		47
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	(148)		(83)
Portion of Deferred Compensation Liability Measured at Fair Value	(172)		(162)
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Net of Unamortized Discount	4,117	[1]	4,114	[1]
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Net of Unamortized Discount	4,606	[1]	4,733	[1]
Quoted Prices in Active Markets (Level 1) [Member]
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	108	[2]	99	[2]
Commodity Derivative Instruments	0	[2]	0	[2]
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	0	[2]	0	[2]
Portion of Deferred Compensation Liability Measured at Fair Value	(172)	[2]	(162)	[2]
Significant Other Observable Inputs (Level 2) [Member]
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	0	[3]	0	[3]
Commodity Derivative Instruments	105	[3]	99	[3]
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	(214)	[3]	(135)	[3]
Portion of Deferred Compensation Liability Measured at Fair Value	0	[3]	0	[3]
Significant Unobservable Inputs (Level 3) [Member]
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	0	[4]	0	[4]
Commodity Derivative Instruments	0	[4]	0	[4]
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	0	[4]	0	[4]
Portion of Deferred Compensation Liability Measured at Fair Value	0	[4]	0	[4]
Fair Value Inputs Adjustment [Member]
Financial Assets Measured at Fair Value on a Recurring Basis [Abstract]
Mutual Fund Investments	0	[5]	0	[5]
Commodity Derivative Instruments	(66)	[5]	(52)	[5]
Financial Liabilities Measured at Fair Value on a Recurring Basis [Abstract]
Commodity Derivative Instruments	66	[5]	52	[5]
Portion of Deferred Compensation Liability Measured at Fair Value	$ 0	[5]	$ 0	[5]

[1] Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at March 31, 2012 or December 31, 2011. See Note 5. Debt

[2] 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.

[3] 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.

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

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