Commitments and Contingencies - 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	$ 25	[1]	$ 28	[1]	$ 83	[2]	$ 86	[2]
Finance Lease, Right-of-Use Asset, Amortization	1		2		3		6
Finance Lease, Interest Expense	4		4		12		12
Finance Lease, Cost	5		6		15		18
Lessee, Operating Lease, Liability, Payments, Due	432				432
Total minimum obligation	454				454
Interest component of obligation	(51)				(51)
Finance Lease, Liability, Undiscounted Excess Amount	(332)				(332)
Operating Lease, Liability	381				381
Finance Lease, Liability	122				122
Less current portion	(79)				(79)				$ (84)
Less current portion	(5)				(5)
Operating lease liabilities	302				302				$ 351
Noncurrent operating and finance lease liabilities	117				117
Short-term Lease, Cost					1		1
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	22		26		70		77
Lessee, Operating Lease, Liability, Payments, Due	388				388
Interest component of obligation	(46)				(46)
Operating Lease, Liability	342				342
Other
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	3	[3]	$ 2	[3]	13	[4]	$ 9	[4]
Lessee, Operating Lease, Liability, Payments, Due	44				44
Interest component of obligation	(5)				(5)
Operating Lease, Liability	$ 39				$ 39

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

[4] Includes immaterial short-term lease expense for 2022 and 2021.