Financial Risk Management Activities (Schedule Of Derivative Instruments Not Designated As Hedging Instruments And Their Impact On Condensed Consolidated Statements Of Operations) (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Gain (loss) recognized on derivatives not designated as hedging instruments	$ (2)	$ (76)	$ (41)	$ 1
Operating Revenues [Member] | Energy-Related Contracts [Member]
Gain (loss) recognized on derivatives not designated as hedging instruments	0	(78)	(42)	9
Energy Costs [Member] | Energy-Related Contracts [Member]
Gain (loss) recognized on derivatives not designated as hedging instruments	$ (2)	$ 2	$ 1	$ (8)