Utility Plant (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Public Utility, Property, Plant and Equipment
Accumulated amortization of capital leases	$ 7,300	$ 2,600
Utility Plant
Distribution plant	7,886,665	7,488,629
Production plant	3,131,578	3,147,987
Transmission plant	1,576,916	1,556,666
General plant	735,298	746,758
Intangible plant (including capitalized software)2	755,430	797,691
Plant acquisition adjustment	242,826	242,826
Underground storage	45,305	43,391
Liquefied natural gas storage	12,628	12,628
Plant held for future use	46,079	46,020
Recoverable Cushion Gas	8,784	8,655
Plant not classified	723,383	316,933
Finance leases, net of accumulated amortization3	99,967	105,020
Less: Accumulated depreciation and amortization	(4,341,789)	(4,031,458)
Subtotal	10,923,070	10,481,746
Construction work in progress	861,801	870,204
Net utility plant	$ 11,784,871	11,351,950
Minimum
Public Utility, Property, Plant and Equipment
Distribution plant, Estimated Useful Life	7 years
Production plant, Estimated Useful Life	3 years
Transmission plant, Estimated Useful Life	44 years
General plant, Estimated Useful Life	5 years
Public Utilities, Property, Plant and Equipment, Intangible, Estimated Useful Life 1	3 years
Underground storage, Estimated Useful Life	25 years
Liquefied natural gas storage, Estimated Useful Life	25 years
Minimum | Franchise Rights [Member]
Public Utility, Property, Plant and Equipment
General plant, Estimated Useful Life	10 years
Minimum | Software and Software Development Costs [Member]
Public Utility, Property, Plant and Equipment
General plant, Estimated Useful Life	3 years
Maximum
Public Utility, Property, Plant and Equipment
Distribution plant, Estimated Useful Life	65 years
Production plant, Estimated Useful Life	90 years
Transmission plant, Estimated Useful Life	75 years
General plant, Estimated Useful Life	75 years
Public Utilities, Property, Plant and Equipment, Intangible, Estimated Useful Life 1	50 years
Underground storage, Estimated Useful Life	60 years
Liquefied natural gas storage, Estimated Useful Life	50 years
Maximum | Franchise Rights [Member]
Public Utility, Property, Plant and Equipment
General plant, Estimated Useful Life	50 years
Maximum | Software and Software Development Costs [Member]
Public Utility, Property, Plant and Equipment
General plant, Estimated Useful Life	10 years
Subsidiaries [Member]
Utility Plant
Distribution plant	$ 9,406,017	9,026,042
Production plant	3,780,910	3,815,599
Transmission plant	1,683,737	1,663,559
General plant	760,094	773,662
Intangible plant (including capitalized software)2	745,973	788,240
Plant acquisition adjustment	282,792	282,792
Underground storage	58,716	56,820
Liquefied natural gas storage	14,498	14,498
Plant held for future use	46,232	46,172
Recoverable Cushion Gas	8,784	8,655
Plant not classified	723,383	316,933
Finance leases, net of accumulated amortization3	99,967	105,020
Less: Accumulated depreciation and amortization	(6,688,033)	(6,416,246)
Subtotal	10,923,070	10,481,746
Construction work in progress	861,801	870,204
Net utility plant	$ 11,784,871	$ 11,351,950