Derivative Instruments And Hedging Activities (Summary Of Gains/(Loss) Amounts Recognized In AOCI) (Details) (Designated As Hedging Instruments [Member], Interest Rate Contract [Member], USD $) In Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2011	Sep. 30, 2010
Designated As Hedging Instruments [Member] | Interest Rate Contract [Member]
Gain/(loss) amounts recognized in AOCI	$ 1	$ 5	$ 2