Commitments And Contingencies (Schedule Of Accrued Liabilities For Environmental Exposures) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Commitments And Contingencies [Line Items]
Beginning balance as of January 1	$ 35
Payments	1
Ending balance as of March 31	34
Less amounts in Other current liabilities	6
Amounts in Other deferred credits	28
Transmission And Distribution [Member]
Commitments And Contingencies [Line Items]
Beginning balance as of January 1	15
Ending balance as of March 31	15
Less amounts in Other current liabilities	2
Amounts in Other deferred credits	13
Regulated [Member]
Commitments And Contingencies [Line Items]
Beginning balance as of January 1	8
Payments	1
Ending balance as of March 31	7
Less amounts in Other current liabilities	2
Amounts in Other deferred credits	5
Non-Regulated [Member]
Commitments And Contingencies [Line Items]
Beginning balance as of January 1	10
Ending balance as of March 31	10
Amounts in Other deferred credits	10
Other [Member]
Commitments And Contingencies [Line Items]
Beginning balance as of January 1	2
Ending balance as of March 31	2
Less amounts in Other current liabilities	$ 2