Commitments and Contingencies, Leases (Details) - USD ($)		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Maximum Length - Short-Term Leases		12 months
Operating Lease, Weighted Average Discount Rate, Percent		4.40%
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		$ 544,000,000	$ 544,000,000
Operating Lease, Right-of-Use Asset, Accumulated Depreciation		(173,000,000)	(141,000,000)
Operating lease right-of-use assets		371,000,000	403,000,000
Lease, Cost [Abstract]
Operating Lease, Cost	[1]	51,000,000	57,000,000	$ 57,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2025		49,000,000
2026		49,000,000
2027		49,000,000
2028		50,000,000
2029		50,000,000
Thereafter		203,000,000
Total minimum obligation		450,000,000
Interest component of obligation		(79,000,000)
Tax credit carryforward		371,000,000
Less current portion		(34,000,000)	(32,000,000)
Operating Lease, Liability, Noncurrent		337,000,000	371,000,000
Weighted Average Remaining lease term, operating		9.1
Property, Plant and Equipment, Other Types [Member]
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		44,000,000	44,000,000
Lease, Cost [Abstract]
Operating Lease, Cost	[2]	3,000,000	4,000,000	4,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2025		3,000,000
2026		3,000,000
2027		3,000,000
2028		4,000,000
2029		4,000,000
Thereafter		29,000,000
Total minimum obligation		46,000,000
Interest component of obligation		(10,000,000)
Tax credit carryforward		36,000,000
Purchased Power Agreements
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		500,000,000	500,000,000
Lease, Cost [Abstract]
Operating Lease, Cost		48,000,000	$ 53,000,000	$ 53,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2025	[3],[4]	46,000,000
2026	[3],[4]	46,000,000
2027	[3],[4]	46,000,000
2028	[3],[4]	46,000,000
2029	[3],[4]	46,000,000
Thereafter	[3],[4]	174,000,000
Total minimum obligation	[3],[4]	404,000,000
Interest component of obligation	[3],[4]	(69,000,000)
Tax credit carryforward	[3],[4]	$ 335,000,000

[1] PPA capacity payments are included in electric fuel and purchased power on the statements of income. Expense for other operating leases is included in O&M expense.

[2] Includes immaterial short-term lease expense for 2024, 2023 and 2022.

[3] Amounts do not include PPAs accounted for as executory contracts and/or contingent payments, such as energy payments on renewable PPAs.

[4] PPA operating leases contractually expire at various dates through 2033.