Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2014

Fair Value Measurements

Assets and liabilities measured at fair value on a recurring basis (in millions)

	Fair Value Measurements at
	June 30, 2014 Using
							Netting and			Total Fair
Description	Level 1		Level 2		Level 3		Collateral (a)			Value
Assets:
Commodity derivatives	$	410	$	176	$	—	$	(553	)	$	33
Liabilities:
Commodity derivatives	$	418	$	244	$	—	$	(578	)	$	84

	Fair Value Measurements at
	December 31, 2013 Using
							Netting and			Total Fair
Description	Level 1		Level 2		Level 3		Collateral (a)			Value
Assets:
Commodity derivatives	$	185	$	195	$	—	$	(329	)	$	51
Liabilities:
Commodity derivatives	$	199	$	223	$	—	$	(364	)	$	58

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