Commitments and Contingencies, Leases (Details) - USD ($)		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Maximum Length - Short-Term Leases		12 months
Short-term Lease, Cost		$ 2,000,000	$ 2,000,000	$ 1,000,000
Operating Lease, Weighted Average Discount Rate, Percent		3.80%
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		$ 630,000,000	632,000,000
Operating Lease, Right-of-Use Asset, Accumulated Depreciation		(222,000,000)	(144,000,000)
Operating lease right-of-use assets		408,000,000	488,000,000
Lease, Cost [Abstract]
Operating Lease, Cost	[1]	104,000,000	97,000,000	85,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022		105,000,000
2023		110,000,000
2024		107,000,000
2025		87,000,000
2026		47,000,000
Thereafter		31,000,000
Total minimum obligation		487,000,000
Interest component of obligation		(44,000,000)
Present value of minimum obligation		443,000,000
Less current portion		(90,000,000)	(85,000,000)
Operating lease liabilities		353,000,000	443,000,000
Weighted Average Remaining lease term, operating		8.5
Property, Plant and Equipment, Other Types [Member]
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		74,000,000	74,000,000
Lease, Cost [Abstract]
Operating Lease, Cost	[2]	8,000,000	8,000,000	9,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022		9,000,000
2023		12,000,000
2024		7,000,000
2025		7,000,000
2026		7,000,000
Thereafter		31,000,000
Total minimum obligation		73,000,000
Interest component of obligation		(12,000,000)
Present value of minimum obligation		61,000,000
Purchased Power Agreements
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		556,000,000	558,000,000
Lease, Cost [Abstract]
Operating Lease, Cost		96,000,000	$ 89,000,000	$ 76,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	[3],[4]	96,000,000
2023	[3],[4]	98,000,000
2024	[3],[4]	100,000,000
2025	[3],[4]	80,000,000
2026	[3],[4]	40,000,000
Thereafter	[3],[4]	0
Total minimum obligation	[3],[4]	414,000,000
Interest component of obligation	[3],[4]	(32,000,000)
Present value of minimum obligation	[3],[4]	$ 382,000,000

[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 short-term lease expense of $2 million, $2 million and $1 million for 2021, 2020 and 2019, respectively.

[3] Amounts do not include PPAs accounted for as executory contracts and/or contingent payments, such as energy payments on renewable PPAs.

[4] PPA operating leases contractually expire at various dates through 2039.