CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating revenue:
Electric	$ 1,010,160	$ 756,377
Natural gas	517,258	426,348
Other	13,769	10,712
Total operating revenue	1,541,187	1,193,437
Energy costs:
Purchased electricity	339,816	238,203
Electric generation fuel	150,254	60,644
Residential exchange	(23,531)	(23,070)
Purchased natural gas	235,482	177,333
Unrealized (gain) loss on derivative instruments, net	192,123	(131,921)
Utility operations and maintenance	194,991	170,300
Non-utility expense and other	16,046	15,419
Depreciation and amortization	188,717	164,576
Conservation amortization	38,219	30,141
Taxes other than income taxes	133,690	121,377
Total operating expenses	1,465,807	823,002
Operating income (loss)	75,380	370,435
Other income (expense):
Other income	13,698	13,164
Other expense	(2,477)	(3,154)
Interest charges:
AFUDC	5,608	4,129
Interest expense	(90,042)	(86,468)
Income (loss) before income taxes	2,167	298,106
Income tax (benefit) expense	2,198	19,811
Net income (loss)	(31)	278,295
Subsidiaries [Member]
Operating revenue:
Electric	1,010,160	756,377
Natural gas	517,258	426,348
Other	9,233	10,677
Total operating revenue	1,536,651	1,193,402
Energy costs:
Purchased electricity	339,816	238,203
Electric generation fuel	150,254	60,644
Residential exchange	(23,531)	(23,070)
Purchased natural gas	235,482	177,333
Unrealized (gain) loss on derivative instruments, net	192,123	(131,921)
Utility operations and maintenance	194,991	170,300
Non-utility expense and other	8,014	12,814
Depreciation and amortization	187,043	163,704
Conservation amortization	38,219	30,141
Taxes other than income taxes	133,264	121,116
Total operating expenses	1,455,675	819,264
Operating income (loss)	80,976	374,138
Other income (expense):
Other income	12,820	10,968
Other expense	(2,477)	(3,154)
Interest charges:
AFUDC	5,608	4,129
Interest expense	(66,983)	(63,144)
Income (loss) before income taxes	29,944	322,937
Income tax (benefit) expense	2,409	34,856
Net income (loss)	$ 27,535	$ 288,081