Debt and Credit Agreements - Summary of Outstanding Long-term Debt (Details) $ in Millions	Jun. 30, 2022 USD ($)
Energy Efficiency Project Financing
Debt Instrument [Line Items]
Amount	$ 6
Minimum | Energy Efficiency Project Financing
Debt Instrument [Line Items]
Interest Rate	2.20%
Maximum | Energy Efficiency Project Financing
Debt Instrument [Line Items]
Interest Rate	2.44%
Senior Notes | Senior Notes, Due March 2022
Debt Instrument [Line Items]
Interest Rate	3.40%
Amount	$ 500
Senior Notes | Senior Notes, Due June 2022
Debt Instrument [Line Items]
Interest Rate	4.25%
Amount	$ 523
Nonrecourse Debt | CR Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	2.50%
Amount	$ 41
Nonrecourse Debt | Continental Wind Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	6.00%
Amount	$ 20
Nonrecourse Debt | West Medway II Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	2.875%
Amount	$ 11
Nonrecourse Debt | Antelope Valley DOE Nonrecourse Debt
Debt Instrument [Line Items]
Amount	$ 8
Nonrecourse Debt | RPG Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	4.11%
Amount	$ 3
Nonrecourse Debt | Energy Efficiency Project Financing Due December 2022
Debt Instrument [Line Items]
Interest Rate	3.71%
Amount	$ 3
Nonrecourse Debt | Minimum | Antelope Valley DOE Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	2.29%
Nonrecourse Debt | Maximum | Antelope Valley DOE Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	3.56%