Intangibles (Schedule of Intangibles) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Line Items]
Retirement of Intangibles	$ (172)	$ (102)
Purchases of Intangible Assets	98	111	$ 98
Sales and Transfers of Intangible Assets	(63)
Impairments	(1)
Intangible Assets	20	158	149
Renewable Energy Credits [Member]
Goodwill [Line Items]
Retirement of Intangibles	(114)	(93)
Purchases of Intangible Assets	89	94
Sales and Transfers of Intangible Assets	(1)
Impairments	0
Intangible Assets	20	46	45
Emissions Allowances [Member]
Goodwill [Line Items]
Retirement of Intangibles	(58)	(9)
Purchases of Intangible Assets	9	17
Sales and Transfers of Intangible Assets	(62)
Impairments	(1)
Intangible Assets	0	$ 112	$ 104
Transfer to Assets Held for Sale	$ 52