Leases (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2025		Jun. 30, 2024		Jun. 30, 2025		Jun. 30, 2024		Dec. 31, 2024
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 10	[1]	$ 14	[1]	$ 20	[2]	$ 28	[2]
Lessee, Operating Lease, Liability, to be Paid	426				426
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(72)				(72)
Operating Lease, Liability	354				354
Operating Lease, Liability, Current	(35)				(35)				$ (34)
Operating lease liabilities	319				319				$ 337
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	9		13		18		26
Lessee, Operating Lease, Liability, to be Paid	381				381
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(62)				(62)
Operating Lease, Liability	319				319
Property, Plant and Equipment, Other Types
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	1	[3]	$ 1	[3]	2	[4]	$ 2	[4]
Lessee, Operating Lease, Liability, to be Paid	45				45
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(10)				(10)
Operating Lease, Liability	$ 35				$ 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] 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.

[3] Includes immaterial short-term lease expense.

[4] Includes immaterial short-term lease expense.