Debt and Credit Agreements - Summary of Outstanding Long-term Debt (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Debt Instrument [Line Items]
Amount	$ (57)	$ (32)
Total long-term debt issued (redeemed)	$ (57)
Nonrecourse \| Tax Exempt Pollution Control Revenue Bonds
Debt Instrument [Line Items]
Interest Rate	4.45%
Amount	$ (23)
Nonrecourse \| Continental Wind Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	6.00%
Amount	$ (18)
Nonrecourse \| West Medway II Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	3.225%
Amount	$ (8)
Nonrecourse \| Antelope Valley DOE Nonrecourse Debt
Debt Instrument [Line Items]
Amount	$ (6)
Nonrecourse \| RPG Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	4.11%
Amount	$ (2)
Nonrecourse \| Minimum \| Antelope Valley DOE Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	2.29%
Nonrecourse \| Maximum \| Antelope Valley DOE Nonrecourse Debt
Debt Instrument [Line Items]
Interest Rate	3.56%

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