Leases (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2023		Sep. 30, 2022		Sep. 30, 2023		Sep. 30, 2022		Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 14	[1]	$ 14	[1]	$ 43	[2]	$ 43	[2]
Lessee, Operating Lease, Liability, to be Paid	513				513
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(102)				(102)
Operating Lease, Liability	411				411
Operating Lease, Liability, Current	(32)				(32)				$ (31)
Operating lease liabilities	379				379				$ 403
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	13		13		40		39
Lessee, Operating Lease, Liability, to be Paid	462				462
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(89)				(89)
Operating Lease, Liability	373				373
Property, Plant and Equipment, Other Types
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	1	[3]	$ 1	[3]	3	[4]	$ 4	[4]
Lessee, Operating Lease, Liability, to be Paid	51				51
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(13)				(13)
Operating Lease, Liability	$ 38				$ 38

[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 for 2023 and 2022.

[4] Includes immaterial short-term lease expense for both 2023 and 2022.