Fair Value Measurements and Disclosures (Tables)

12 Months Ended

Dec. 31, 2011

Fair Value Measurements and Disclosures [Abstract]

Assets and liabilities measured at fair value on a recurring basis

Measurement information for assets and liabilities that are measured at fair value on a recurring basis was as follows:

	Fair Value Measurements Using
	Quoted Prices in  Active Markets  (Level 1) (1)			Significant Other  Observable Inputs  (Level 2) (1)			Significant  Unobservable Inputs  (Level 3) (1)		Adjustment (2)			Fair Value  Measurement
(millions)
December 31, 2011
Financial Assets
Mutual Fund Investments	$	99		$	-		$	-	$	-		$	99
Commodity Derivative Instruments		-			99			-		(52	)		47
Financial Liabilities
Commodity Derivative Instruments		-			(135	)		-		52			(83	)
Portion of Deferred Compensation
Liability Measured at Fair Value		(162	)		-			-		-			(162	)
December 31, 2010
Financial Assets
Mutual Fund Investments	$	112		$	-		$	-	$	-		$	112
Commodity Derivative Instruments		-			106			-		(44	)		62
Financial Liabilities
Commodity Derivative Instruments		-			(119	)		-		44			(75	)
Interest Rate Derivative Instrument		-			(63	)		-		-			(63	)
Portion of Deferred Compensation
Liability Measured at Fair Value		(178	)		-			-		-			(178	)

(1) See Note 1. Summary of Significant Accounting Policies - Fair Value Measurements for a description of the fair value hierarchy.

(2) Amount represents the impact of master netting agreements that allow us to settle asset and liability positions with the same counterparty.

Assets and liabilities measured at fair value on a nonrecurring basis

Information about impaired assets as of the date of the assessment is as follows:

	Fair Value Measurements Using
Description	Quoted Prices in Active Markets  (Level 1) (1)		Significant Other Observable Inputs  (Level 2) (1)		Significant  Unobservable Inputs  (Level 3) (1)		Net Book Value (2)		Total Pre-tax  (Non-cash)  Impairment Loss
(millions)
Year Ended December 31, 2011
Impaired Oil and Gas Properties	$	-	$	-	$	213	$	972	$	759
Year Ended December 31, 2010
Impaired US Oil and Gas Properties		-		-		30		174		144
Year Ended December 31, 2009
Impaired US Oil and Gas Properties		-		-		363		867		504
Impaired Investment in Ecuador		-		-		72		172		100

(1) See Note 1. Summary of Significant Accounting Policies - Fair Value Measurements for a description of the fair value hierarchy.

(2) Amount represents net book value at date of assessment.

Additional fair value disclosures

Fair value information regarding our debt is as follows:

	December 31,
	2011				2010
	Carrying  Amount		Fair Value		Carrying  Amount		Fair Value
(millions)
Debt, Net of Unamortized Discount (1)	$	4,114	$	4,733	$	1,977	$	2,302

(1) Excludes Aseng FPSO lease obligation.