Leases (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2024		Jun. 30, 2023		Jun. 30, 2024		Jun. 30, 2023	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		$ 14	[1]	$ 15	[1]	$ 28	[1]	$ 29
Lessee, Operating Lease, Liability, to be Paid		476				476
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(89)				(89)
Operating Lease, Liability		387				387
Operating Lease, Liability, Current		(33)				(33)			$ (32)
Operating lease liabilities		354				354			$ 371
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		13		14		26		27
Lessee, Operating Lease, Liability, to be Paid		428				428
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(77)				(77)
Operating Lease, Liability		351				351
Property, Plant and Equipment, Other Types
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	[2]	1		$ 1		2		$ 2
Lessee, Operating Lease, Liability, to be Paid		48				48
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(12)				(12)
Operating Lease, Liability		$ 36				$ 36

[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 2024 and 2023.