Leases (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2022		Sep. 30, 2021		Sep. 30, 2022		Sep. 30, 2021		Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 14	[1]	$ 13	[1]	$ 43	[2]	$ 42	[2]
Lessee, Operating Lease, Liability, to be Paid	562				562
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(120)				(120)
Operating Lease, Liability	442				442
Operating Lease, Liability, Current	(31)				(31)				$ (30)
Operating lease liabilities	411				411				$ 434
Short-term Lease, Cost					1		1
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	13		13		39		40
Lessee, Operating Lease, Liability, to be Paid	508				508
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(106)				(106)
Operating Lease, Liability	402				402
Property, Plant and Equipment, Other Types
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	1	[3]	$ 0	[3]	4	[4]	$ 2	[4]
Lessee, Operating Lease, Liability, to be Paid	54				54
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(14)				(14)
Operating Lease, Liability	$ 40				$ 40

[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 2022 and 2021.

[4] Includes short-term lease expense of $1 million for 2022 and 2021, respectively.