Derivative Instruments And Hedging Activities (Derivative Gain (Loss) Amounts Recognized In Income) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Derivative Instruments, Gain (Loss) [Line Items]
Total net losses		$ 9
Total Earnings [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized gains (losses)		2	(2)
Unrealized mark-to-market losses	(30)	(3)	(2)
Total net losses	$ (30)	$ (1)	$ (4)