Goodwill, Intangible Assets And Impairments (Goodwill By Reportable Operating Segment) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Goodwill before accumulated impairment charges	$ 4,720		$ 4,729
Goodwill accumulated impairment charges	(871)	(871)
Foreign Exchange and Other Changes	(9)
Goodwill as adjusted for accumulated impairment charges	3,849	3,858
U.S. Franchised Electric And Gas [Member]
Goodwill before accumulated impairment charges	3,483		3,483
Goodwill as adjusted for accumulated impairment charges	3,483	3,483
Commercial Power [Member]
Goodwill before accumulated impairment charges	940		940
Goodwill accumulated impairment charges	(871)	(871)
Goodwill as adjusted for accumulated impairment charges	69	69
International [Member]
Goodwill before accumulated impairment charges	297		306
Foreign Exchange and Other Changes	(9)
Goodwill as adjusted for accumulated impairment charges	$ 297	$ 306

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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- Definition

The increase (decrease) in the recorded value of goodwill for foreign currency translation adjustments and purchase accounting adjustments needed to revise the carrying amount of goodwill to fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

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