Commitments and Contingencies - Leases (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2022		Jun. 30, 2021		Jun. 30, 2022		Jun. 30, 2021		Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	$ 27	[1]	$ 29	[1]	$ 58	[2]	$ 58	[2]
Finance Lease, Right-of-Use Asset, Amortization	1		2		2		4
Finance Lease, Interest Expense	4		4		8		8
Finance Lease, Cost	5		6		10		12
Lessee, Operating Lease, Liability, Payments, Due	456				456
Total minimum obligation	449				449
Interest component of obligation	(55)				(55)
Finance Lease, Liability, Undiscounted Excess Amount	(326)				(326)
Operating Lease, Liability	401				401
Finance Lease, Liability	123				123
Less current portion	(79)				(79)				$ (84)
Less current portion	(5)				(5)
Operating lease liabilities	322				322				$ 351
Noncurrent operating and finance lease liabilities	118				118
PPAs
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	23		26		48		51
Lessee, Operating Lease, Liability, Payments, Due	409				409
Interest component of obligation	(50)				(50)
Operating Lease, Liability	359				359
Other
Lessee, Lease, Description [Line Items]
Operating Lease, Cost	4	[3]	$ 3	[3]	10	[4]	$ 7	[4]
Lessee, Operating Lease, Liability, Payments, Due	47				47
Interest component of obligation	(5)				(5)
Operating Lease, Liability	$ 42				$ 42

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

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