Leases (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	[1]	$ 14	$ 14
Lessee, Operating Lease, Liability, to be Paid		488
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(93)
Operating Lease, Liability		395
Operating Lease, Liability, Current		(33)		$ (32)
Operating lease liabilities		362		$ 371
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		13	13
Lessee, Operating Lease, Liability, to be Paid		439
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(81)
Operating Lease, Liability		358
Property, Plant and Equipment, Other Types
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	[2]	1	$ 1
Lessee, Operating Lease, Liability, to be Paid		49
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(12)
Operating Lease, Liability		$ 37

[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.