Goodwill (Rollforward of Goodwill) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill balance	$ 19,425	$ 19,425
Accumulated impairment charges	(122)	(122)
Goodwill balance, adjusted for accumulated impairment charges	19,303	19,303
Electric Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill balance	17,379	17,379
Goodwill balance, adjusted for accumulated impairment charges	17,379	17,379
Gas Utilities and Infrastructure [Member]
Goodwill [Line Items]
Goodwill balance	1,924	1,924
Goodwill balance, adjusted for accumulated impairment charges	1,924	1,924
Commercial Renewables [Member]
Goodwill [Line Items]
Goodwill balance	122	122
Accumulated impairment charges	$ (122)	$ (122)

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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-Publisher FASB
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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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