Derivative Instruments (Details 4) (Not Designated as Hedging Instrument, Subject to Regulatory Accounting, Excluded from Earnings, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Derivative [Line Items]
Unrealized Gain (Loss) on Derivative Instrument	$ 31		$ 16
Realized Gain (Loss) on Derivative Instrument	(11)		22
NUGs
Derivative [Line Items]
Unrealized Gain (Loss) on Derivative Instrument	27		18
Realized Gain (Loss) on Derivative Instrument	(10)		23
LCAPP
Derivative [Line Items]
Unrealized Gain (Loss) on Derivative Instrument	0	[1]	(2)	[1]
Realized Gain (Loss) on Derivative Instrument	0	[1]	0	[1]
Regulated FTRs
Derivative [Line Items]
Unrealized Gain (Loss) on Derivative Instrument	4		0
Realized Gain (Loss) on Derivative Instrument	$ (1)		$ (1)

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