Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2012

Fair Value Measurements

Assets and liabilities measured at fair value on a recurring basis

	Fair Value Measurements at March 31, 2012 Using									Netting and				Total Fair
Description	Level 1			Level 2			Level 3			Collateral (a)				Value
Assets:
Commodity derivatives		$	722		$	752		$	—		$	(1,234	)		$	240
Liabilities:
Commodity derivatives		$	782		$	738		$	—		$	(1,331	)		$	189

	Fair Value Measurements at December 31, 2011 Using									Netting and				Total Fair
Description	Level 1			Level 2			Level 3			Collateral(a)				Value
Assets:
Commodity derivatives		$	310		$	640		$	—		$	(758	)		$	192
Liabilities:
Commodity derivatives		$	311		$	652		$	—		$	(782	)		$	181

(a)Represents the impact of netting assets, liabilities and collateral when a legal right of offset exists.