Derivative And Hedging Activities (Schedule Of Derivative Instruments, Gain (Loss) In Statement Of Financial Performance) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in net income (loss)	$ (4)	$ 1
Interest Rate Contracts [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in net income (loss)	(6)	(5)
Fair Value Derivatives [Member] | Interest Rate Contracts [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in net income (loss)	$ 2	$ 6