Variable Interest Entities (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Variable Interest Entity [Line Items]
Investments	$ 73	$ 76
Securitization bonds
Variable Interest Entity [Line Items]
Total principal amount outstanding	787	787
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Regulatory asset	750	778
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investments	$ 71	$ 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%