Derivative Instruments and Hedging Activities (Fair Value Of Derivatives Designated As Hedging Instruments) (Details) (Designated As Hedging Instrument [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Designated As Hedging Instrument [Member]
Derivative [Line Items]
Interest Rate Derivative Assets, at Fair Value	$ 21	$ 0
Interest Rate Derivative Liabilities, at Fair Value	0	9
Derivative Instruments in Hedges, Assets, at Fair Value	21	0
Derivative Instruments in Hedges, Liabilities, at Fair Value	$ 0	$ 9