Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Current Assets:
Cash and cash equivalents	$ 10,141	$ 21,302
Accounts receivable, less reserves	41,490	51,277
Other accounts receivables, less reserves	12,358	10,067
Unbilled revenues	27,355	35,833
Materials and supplies, at average cost	37,943	36,187
Fuel for electric generation, at average cost	10,318	11,521
Stored natural gas, at average cost	19,865	19,937
Prepaid taxes	13,716	18,390
Regulatory assets - current	7,147	8,522
Other current assets	14,693	14,229
Total Current Assets	195,026	227,265
Regulatory assets	40,479	36,764
Pension benefit asset	140,931	132,264
Other deferred assets and other	18,606	26,285
Property, Plant, and Equipment:
Property, plant, and equipment, net	2,248,793	2,149,138
Construction work in progress	219,938	138,208
Total Property, Plant, and Equipment	2,468,731	2,287,346
Investments	126,963	118,035
Total Assets	2,990,736	2,827,959
Current Liabilities:
Long-term debt due within one year	20,395	5,285
Short-term debt	76,001	0
Accounts payable	67,058	77,466
Accrued interest and taxes	11,476	11,558
Accrued payroll related items	15,894	15,870
Regulatory liabilities - current	16,146	7,966
Other current liabilities	8,141	7,418
Total Current Liabilities	215,111	125,563
Other Credits:
Deferred income taxes	320,660	316,397
Investment tax credit - deferred	49,227	44,988
Regulatory liabilities	169,991	163,336
Accrued pension and other postretirement benefits	51,037	50,155
Asset retirement obligations	75,979	69,132
Other deferred liabilities and other	66,031	64,553
Total Other Credits	732,925	708,561
Capitalization:
Common shareholders equity	1,297,653	1,230,138
Long-term debt	745,047	763,697
Total Capitalization	2,042,700	1,993,835
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	2,990,736	2,827,959
MGE [Member]
Current Assets:
Cash and cash equivalents	3,249	16,865
Accounts receivable, less reserves	41,490	51,277
Other accounts receivables, less reserves	12,353	10,063
Unbilled revenues	27,355	35,833
Materials and supplies, at average cost	37,943	36,187
Fuel for electric generation, at average cost	10,318	11,521
Stored natural gas, at average cost	19,865	19,937
Prepaid taxes	13,679	18,359
Regulatory assets - current	7,147	8,522
Other current assets	15,234	14,740
Total Current Assets	188,633	223,304
Regulatory assets	40,479	36,764
Pension benefit asset	140,931	132,264
Other deferred assets and other	18,010	25,690
Property, Plant, and Equipment:
Property, plant, and equipment, net	2,248,821	2,149,165
Construction work in progress	219,938	138,208
Total Property, Plant, and Equipment	2,468,759	2,287,373
Total Assets	2,856,812	2,705,395
Current Liabilities:
Long-term debt due within one year	20,395	5,285
Short-term debt	76,001	0
Accounts payable	67,027	77,453
Accrued interest and taxes	10,971	11,866
Accrued payroll related items	15,894	15,870
Regulatory liabilities - current	16,146	7,966
Other current liabilities	8,141	7,418
Total Current Liabilities	214,575	125,858
Other Credits:
Deferred income taxes	284,523	280,961
Investment tax credit - deferred	49,227	44,988
Regulatory liabilities	169,991	163,336
Accrued pension and other postretirement benefits	51,037	50,155
Asset retirement obligations	75,979	69,132
Other deferred liabilities and other	69,591	67,463
Total Other Credits	700,348	676,035
Capitalization:
Common shareholders equity	1,040,975	989,419
Noncontrolling interest	155,867	150,386
Total Equity	1,196,842	1,139,805
Long-term debt	745,047	763,697
Total Capitalization	1,941,889	1,903,502
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	$ 2,856,812	$ 2,705,395