Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Current Assets:
Cash and cash equivalents	$ 16,687	$ 11,140
Accounts receivable, less reserves	45,342	46,734
Other accounts receivables, less reserves	9,687	15,618
Unbilled revenues	32,775	33,181
Materials and supplies, at average cost	34,417	33,385
Fuel for electric generation, at average cost	13,563	13,423
Stored natural gas, at average cost	21,696	25,840
Prepaid taxes	14,348	22,310
Regulatory assets - current	20,037	20,979
Other current assets	13,193	15,587
Total Current Assets	221,745	238,197
Regulatory assets	80,643	81,589
Pension benefit asset	96,525	93,896
Other deferred assets and other	20,595	20,741
Property, Plant, and Equipment:
Property, plant, and equipment, net	2,029,858	2,018,121
Construction work in progress	110,049	110,091
Total Property, Plant, and Equipment	2,139,907	2,128,212
Investments	114,661	112,823
Total Assets	2,674,076	2,675,458
Current Liabilities:
Long-term debt due within one year	5,180	5,146
Short-term debt	41,000	38,000
Accounts payable	41,594	65,451
Accrued interest and taxes	7,601	9,372
Accrued payroll related items	12,422	15,888
Regulatory liabilities - current	25,804	15,296
Other current liabilities	6,054	8,003
Total Current Liabilities	139,655	157,156
Other Credits:
Deferred income taxes	283,421	279,029
Investment tax credit - deferred	46,416	46,892
Regulatory liabilities	157,272	162,316
Accrued pension and other postretirement benefits	55,279	55,058
Asset Retirement Obligations, Noncurrent	55,532	54,430
Other deferred liabilities and other	60,072	61,682
Total Other Credits	657,992	659,407
Capitalization:
Common shareholders equity	1,158,783	1,140,073
Long-term debt	717,646	718,822
Total Capitalization	1,876,429	1,858,895
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	2,674,076	2,675,458
MGE [Member]
Current Assets:
Cash and cash equivalents	6,279	2,819
Accounts receivable, less reserves	45,342	46,734
Other accounts receivables, less reserves	9,682	15,616
Unbilled revenues	32,775	33,181
Materials and supplies, at average cost	34,417	33,385
Fuel for electric generation, at average cost	13,563	13,423
Stored natural gas, at average cost	21,696	25,840
Prepaid taxes	15,062	22,338
Regulatory assets - current	20,037	20,979
Other current assets	13,681	16,088
Total Current Assets	212,534	230,403
Regulatory assets	80,643	81,589
Pension benefit asset	96,525	93,896
Other deferred assets and other	20,534	20,780
Property, Plant, and Equipment:
Property, plant, and equipment, net	2,029,886	2,018,149
Construction work in progress	110,049	110,091
Total Property, Plant, and Equipment	2,139,935	2,128,240
Investments	59	60
Total Assets	2,550,230	2,554,968
Current Liabilities:
Long-term debt due within one year	5,180	5,146
Short-term debt	41,000	38,000
Accounts payable	41,579	65,434
Accrued interest and taxes	7,557	9,325
Accrued payroll related items	12,422	15,888
Regulatory liabilities - current	25,804	15,296
Other current liabilities	6,437	6,502
Total Current Liabilities	139,979	155,591
Other Credits:
Deferred income taxes	248,763	244,634
Investment tax credit - deferred	46,416	46,892
Regulatory liabilities	157,272	162,316
Accrued pension and other postretirement benefits	55,279	55,058
Asset Retirement Obligations, Noncurrent	55,532	54,430
Other deferred liabilities and other	61,887	63,969
Total Other Credits	625,149	627,299
Capitalization:
Common shareholders equity	916,328	903,725
Noncontrolling interest	151,128	149,531
Total Equity	1,067,456	1,053,256
Long-term debt	717,646	718,822
Total Capitalization	1,785,102	1,772,078
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	$ 2,550,230	$ 2,554,968