Commitments and Contingencies - 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	$ 28	[1]	$ 27	[1]	$ 55	[2]	$ 58	[2]
Finance Lease, Right-of-Use Asset, Amortization	0		1		1		2
Finance Lease, Interest Expense	4		4		8		8
Finance Lease, Cost	4		5		9		10
Lessee, Operating Lease, Liability, Payments, Due	483				483
Total minimum obligation	427				427
Interest component of obligation	(50)				(50)
Finance Lease, Liability, Undiscounted Excess Amount	(311)				(311)
Operating Lease, Liability	433				433
Finance Lease, Liability	116				116
Less current portion	(93)				(93)				$ (80)
Less current portion	(3)				(3)
Operating lease liabilities	340				340				$ 379
Noncurrent operating and finance lease liabilities	113				113
Short-term Lease, Cost	1				1
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	23		23		45		48
Lessee, Operating Lease, Liability, Payments, Due	416				416
Interest component of obligation	(43)				(43)
Operating Lease, Liability	373				373
Other
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	5	[3]	$ 4	[3]	10	[4]	$ 10	[4]
Lessee, Operating Lease, Liability, Payments, Due	67				67
Interest component of obligation	(7)				(7)
Operating Lease, Liability	$ 60				$ 60

[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] 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.

[3] Includes $1 million of short-term lease expense for 2023 and an immaterial short-term lease expense for 2022.

[4] Includes $1 million of short-term lease expense for 2023 and an immaterial short-term lease expense for 2022.