Goodwill and Other Intangible Assets (Intangible Assets Acquired) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Indefinite-lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 822	$ 454
Computer Software, Intangible Asset [Member]
Indefinite-lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 89	$ 35
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years	4 years
Other Intangible Assets [Member]
Indefinite-lived Intangible Assets [Line Items]
Other intangible assets acquired	$ 2	$ 22
Contracts
Indefinite-lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 35	$ 28
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	12 years	20 years
Project Development Rights [Member]
Indefinite-lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 667	$ 109
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	35 years	30 years
Emission allowances [Member]
Indefinite-lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 22	$ 56
Transmission Rights [Member]
Indefinite-lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired		$ 20
Compensation from Concession Agreement
Indefinite-lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	12 years	12 years
Transmission Rights [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived Intangible Assets Acquired	$ 0
Compensation from Concession Agreement
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived Intangible Assets Acquired	$ 7	$ 184