Derivative Instruments (Details 5) (Not Designated as Hedging Instrument, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Outstanding net asset (liability) [Roll Forward]
Outstanding net asset (liability), Beginning Balance	$ (202)		$ (398)
Additions/Change in value of existing contracts	31		16
Settled contracts	(11)		22
Outstanding net asset (liability), Ending Balance	(182)		(360)
NUGs
Outstanding net asset (liability) [Roll Forward]
Outstanding net asset (liability), Beginning Balance	(202)		(254)
Additions/Change in value of existing contracts	27		18
Settled contracts	(10)		23
Outstanding net asset (liability), Ending Balance	(185)		(213)
LCAPP
Outstanding net asset (liability) [Roll Forward]
Outstanding net asset (liability), Beginning Balance	0	[1]	(144)	[1]
Additions/Change in value of existing contracts	0	[1]	(2)	[1]
Settled contracts	0	[1]	0	[1]
Outstanding net asset (liability), Ending Balance	0	[1]	(146)	[1]
Regulated FTRs
Outstanding net asset (liability) [Roll Forward]
Outstanding net asset (liability), Beginning Balance	0		0
Additions/Change in value of existing contracts	4		0
Settled contracts	(1)		(1)
Outstanding net asset (liability), Ending Balance	$ 3		$ (1)

[1] During the fourth quarter of 2013, all LCAPP contracts were terminated as discussed above.