Leases (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2023		Jun. 30, 2022		Jun. 30, 2023		Jun. 30, 2022		Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 15	[1]	$ 14	[1]	$ 29	[2]	$ 29	[2]
Lessee, Operating Lease, Liability, to be Paid	525				525
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(106)				(106)
Operating Lease, Liability	419				419
Operating Lease, Liability, Current	(32)				(32)				$ (31)
Operating lease liabilities	387				387				$ 403
Short-term Lease, Cost	1				1
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	14		13		27		26
Lessee, Operating Lease, Liability, to be Paid	474				474
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(93)				(93)
Operating Lease, Liability	381				381
Property, Plant and Equipment, Other Types
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	1		$ 1		2	[3]	$ 3	[3]
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 $1 million of short-term lease expense for 2023 and an immaterial short-term lease expense for 2022.