Commitments and Contingencies, Leases (Details) - USD ($)		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Maximum Length - Short-Term Leases		12 months
Operating Lease, Weighted Average Discount Rate, Percent		4.20%
Short-term Lease, Cost		$ 1,000,000
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		692,000,000	$ 677,000,000
Operating Lease, Right-of-Use Asset, Accumulated Depreciation		(255,000,000)	(268,000,000)
Operating lease right-of-use assets		437,000,000	409,000,000
Finance Lease, Assets and Liabilities, Lessee [Abstract]
Finance Lease, Right-of-Use Asset, Gross		181,000,000	222,000,000
Finance Lease, Right-of-Use Asset, Accumulated Depreciation		(64,000,000)	(97,000,000)
Finance Lease, Right-of-Use Asset		117,000,000	125,000,000
Lease, Cost [Abstract]
Operating Lease, Cost	[1]	111,000,000	118,000,000	$ 113,000,000
Finance Lease, Right-of-Use Asset, Amortization		4,000,000	7,000,000	7,000,000
Finance Lease, Interest Expense		16,000,000	17,000,000	18,000,000
Finance Lease, Cost		20,000,000	24,000,000	25,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Lessee, Operating Lease, Liability, to be Paid, Year One		98,000,000
Lessee, Operating Lease, Liability, to be Paid, Year Two		110,000,000
Lessee, Operating Lease, Liability, to be Paid, Year Three		103,000,000
Lessee, Operating Lease, Liability, to be Paid, Year Four		81,000,000
2027		51,000,000
Thereafter		73,000,000
Total minimum obligation		516,000,000
Interest component of obligation		(57,000,000)
Operating lease liabilities		459,000,000
Less current portion		(80,000,000)	(84,000,000)
Operating lease liabilities		379,000,000	351,000,000
Weighted Average Remaining lease term, operating		5.4
Weighted Average Remaining lease term, finance		37.8
Lessee, Finance Lease, Description [Abstract]
2023		18,000,000
2024		18,000,000
2025		18,000,000
2026		18,000,000
2027		16,000,000
Thereafter		348,000,000
Total minimum obligation		436,000,000
Interest component of obligation		(319,000,000)
Present value of minimum obligation		117,000,000
Less current portion		(3,000,000)
Noncurrent operating and finance lease liabilities		$ 114,000,000
WYCO, Inc. [Member]
Lessee, Finance Lease, Description [Abstract]
Equity Method Investment, Ownership Percentage		50.00%
Property, Plant and Equipment, Other Types [Member]
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		$ 80,000,000	77,000,000
Lease, Cost [Abstract]
Operating Lease, Cost	[2]	20,000,000	16,000,000	13,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Lessee, Operating Lease, Liability, to be Paid, Year One		18,000,000
Lessee, Operating Lease, Liability, to be Paid, Year Two		18,000,000
Lessee, Operating Lease, Liability, to be Paid, Year Three		12,000,000
Lessee, Operating Lease, Liability, to be Paid, Year Four		7,000,000
2027		7,000,000
Thereafter		14,000,000
Total minimum obligation		76,000,000
Interest component of obligation		(8,000,000)
Operating lease liabilities		68,000,000
Gas Storage Facilities [Member]
Finance Lease, Assets and Liabilities, Lessee [Abstract]
Finance Lease, Right-of-Use Asset, Gross		160,000,000	201,000,000
Gas Pipeline
Finance Lease, Assets and Liabilities, Lessee [Abstract]
Finance Lease, Right-of-Use Asset, Gross		21,000,000	21,000,000
Purchased Power Agreements
Operating Lease, Assets and Liabilities, Lessee [Abstract]
Operating Lease, Right-of-Use Asset, Gross		612,000,000	600,000,000
Lease, Cost [Abstract]
Operating Lease, Cost		91,000,000	$ 102,000,000	$ 100,000,000
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Lessee, Operating Lease, Liability, to be Paid, Year One	[3],[4]	80,000,000
Lessee, Operating Lease, Liability, to be Paid, Year Two	[3],[4]	92,000,000
Lessee, Operating Lease, Liability, to be Paid, Year Three	[3],[4]	91,000,000
Lessee, Operating Lease, Liability, to be Paid, Year Four	[3],[4]	74,000,000
2027	[3],[4]	44,000,000
Thereafter	[3],[4]	59,000,000
Total minimum obligation	[3],[4]	440,000,000
Interest component of obligation	[3],[4]	(49,000,000)
Operating lease liabilities	[3],[4]	$ 391,000,000

[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 $1 million for 2022, 2021 and 2020.

[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 2032.