Commitments And Contingencies (Schedule Of Accrued Liabilities For Environmental Exposures) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Beginning balance as of January 1	$ 34
Accruals	3
Payments	(2)
Ending balance as of December 31	35
Less amounts in Other Current Liabilities	6
Amounts in Other Deferred Credits	29
Transmission And Distribution [Member]
Beginning balance as of January 1	13
Accruals	3
Payments	(1)
Ending balance as of December 31	15
Less amounts in Other Current Liabilities	2
Amounts in Other Deferred Credits	13
Regulated [Member]
Beginning balance as of January 1	9
Payments	(1)
Ending balance as of December 31	8
Less amounts in Other Current Liabilities	2
Amounts in Other Deferred Credits	6
Non-Regulated [Member]
Beginning balance as of January 1	10
Ending balance as of December 31	10
Amounts in Other Deferred Credits	10
Other [Member]
Beginning balance as of January 1	2
Ending balance as of December 31	2
Less amounts in Other Current Liabilities	$ 2