Commitments and Contingencies - 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]	$ 26	$ 27
Finance Lease, Right-of-Use Asset, Amortization		1	1
Finance Lease, Interest Expense		4	4
Finance Lease, Cost		5	5
Lessee, Operating Lease, Liability, Payments, Due		403
Total minimum obligation		413
Interest component of obligation		(37)
Finance Lease, Liability, Undiscounted Excess Amount		(300)
Operating Lease, Liability		366
Finance Lease, Liability		113
Less current portion		(102)		$ (102)
Less current portion		(3)
Operating lease liabilities		264		$ 290
Noncurrent operating and finance lease liabilities		110
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost		21	22
Lessee, Operating Lease, Liability, Payments, Due		348
Interest component of obligation		(31)
Operating Lease, Liability		317
Other
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	[2]	5	$ 5
Lessee, Operating Lease, Liability, Payments, Due		55
Interest component of obligation		(6)
Operating Lease, Liability		$ 49

[1] PPA capacity payments are included in electric fuel and purchased power on the consolidated statements of income. Expense for other operating leases is included in O&M expense and electric fuel and purchased power.

[2] Includes immaterial short-term lease expense for both 2024 and 2023.