Summary of Significant Accounting Policies and Other Matters - Long-Lived and Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 1,219,000,000	$ 1,290,000,000
Accumulated amortization		297,000,000
Amortization of intangible assets	71,000,000	95,000,000	$ 102,000,000
Amortization expense, year 1	0
Amortization expense, year 2	0
Amortization expense, year 3	0
Amortization expense, year 4	0
Amortization expense, year 5	0
Impairment charges	0	0
Power Purchase Agreements
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	359,000,000	288,000,000
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	2,000,000	2,000,000
Accumulated amortization	$ 9,000,000	$ 9,000,000