Variable Interest Entities (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
Investments	$ 74	$ 76
Securitization bonds
Variable Interest Entity [Line Items]
Total principal amount outstanding	715	787
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Regulatory asset	695	778
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investments	$ 69	$ 74
Variable Interest Entity, Not Primary Beneficiary | T.E.S. Filer City
Variable Interest Entity [Line Items]
Ownership interest	50.00%
Variable Interest Entity, Not Primary Beneficiary | Grayling
Variable Interest Entity [Line Items]
Ownership interest	50.00%
Variable Interest Entity, Not Primary Beneficiary | Craven
Variable Interest Entity [Line Items]
Ownership interest	50.00%
Variable Interest Entity, Not Primary Beneficiary | Genesee
Variable Interest Entity [Line Items]
Ownership interest	50.00%