Leases (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	[1]	$ 10	$ 14
Lessee, Operating Lease, Liability, to be Paid		438
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(76)
Operating Lease, Liability		362
Operating Lease, Liability, Current		(34)		$ (34)
Operating lease liabilities		328		$ 337
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		9	13
Lessee, Operating Lease, Liability, to be Paid		393
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(66)
Operating Lease, Liability		327
Property, Plant and Equipment, Other Types
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	[2]	1	$ 1
Lessee, Operating Lease, Liability, to be Paid		45
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(10)
Operating Lease, Liability		$ 35

[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 operating and maintenance expense and electric fuel and purchased power.

[2] Includes immaterial short-term lease expense for 2025 and 2024.