Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2011

Fair Value Measurements

Assets and liabilities measured at fair value on a recurring basis

The following tables provide fair value measurement information for such assets and liabilities that are measured on a recurring basis as of June 30, 2011 and December 31, 2010 (in millions):

	Fair Value Measurements at June 30, 2011 Using						Netting and			Total Fair
Description	Level 1		Level 2		Level 3		Collateral (a)			Value
Assets:
Trading equity securities — natural resources industry	$	135	$	—	$	—	$	—		$	135
Commodity derivatives	481		608		—		(801		)	288
Total assets	$	616	$	608	$	—	$	(801	)	$	423
Liabilities:
Commodity derivatives	$	377	$	764	$	—	$	(830	)	$	311
Total liabilities	$	377	$	764	$	—	$	(830	)	$	311

	Fair Value Measurements at December 31, 2010 Using						Netting and			Total Fair
Description	Level 1		Level 2		Level 3		Collateral (a)			Value
Assets:
Trading equity securities — natural resources industry	$	116	$	—	$	—	$	—		$	116
Trading U.S. treasury securities	10		—		—		—			10
Commodity derivatives	178		797		—		(680		)	295
Total assets	$	304	$	797	$	—	$	(680	)	$	421
Liabilities:
Commodity derivatives	$	201	$	916	$	—	$	(736	)	$	381
Total liabilities	$	201	$	916	$	—	$	(736	)	$	381

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