Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Current Assets:
Cash and cash equivalents	$ 10,569	$ 21,302
Accounts receivable, less reserves	43,308	51,277
Other accounts receivables, less reserves	10,239	10,067
Unbilled revenues	29,815	35,833
Materials and supplies, at average cost	37,958	36,187
Fuel for electric generation, at average cost	11,706	11,521
Stored natural gas, at average cost	16,543	19,937
Prepaid taxes	17,946	18,390
Regulatory assets - current	6,317	8,522
Other current assets	13,851	14,229
Total Current Assets	198,252	227,265
Regulatory assets	41,313	36,764
Pension benefit asset	138,063	132,264
Other deferred assets and other	18,505	26,285
Property, Plant, and Equipment:
Property, plant, and equipment, net	2,238,086	2,149,138
Construction work in progress	102,648	138,208
Total Property, Plant, and Equipment	2,340,734	2,287,346
Investments	123,670	118,035
Total Assets	2,860,537	2,827,959
Current Liabilities:
Long-term debt due within one year	5,358	5,285
Short-term debt	5,500	0
Accounts payable	50,344	77,466
Accrued interest and taxes	10,048	11,558
Accrued payroll related items	13,696	15,870
Regulatory liabilities - current	15,812	7,966
Other current liabilities	9,079	7,418
Total Current Liabilities	109,837	125,563
Other Credits:
Deferred income taxes	316,017	316,397
Investment tax credit - deferred	49,702	44,988
Regulatory liabilities	164,177	163,336
Accrued pension and other postretirement benefits	50,583	50,155
Asset retirement obligations	73,739	69,132
Other deferred liabilities and other	65,235	64,553
Total Other Credits	719,453	708,561
Capitalization:
Common shareholders equity	1,269,973	1,230,138
Long-term debt	761,274	763,697
Total Capitalization	2,031,247	1,993,835
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	2,860,537	2,827,959
MGE [Member]
Current Assets:
Cash and cash equivalents	3,525	16,865
Accounts receivable, less reserves	43,308	51,277
Other accounts receivables, less reserves	10,235	10,063
Unbilled revenues	29,815	35,833
Materials and supplies, at average cost	37,958	36,187
Fuel for electric generation, at average cost	11,706	11,521
Stored natural gas, at average cost	16,543	19,937
Prepaid taxes	17,938	18,359
Regulatory assets - current	6,317	8,522
Other current assets	14,336	14,740
Total Current Assets	191,681	223,304
Regulatory assets	41,313	36,764
Pension benefit asset	138,063	132,264
Other deferred assets and other	17,921	25,690
Property, Plant, and Equipment:
Property, plant, and equipment, net	2,238,114	2,149,165
Construction work in progress	102,648	138,208
Total Property, Plant, and Equipment	2,340,762	2,287,373
Total Assets	2,729,740	2,705,395
Current Liabilities:
Long-term debt due within one year	5,358	5,285
Short-term debt	5,500	0
Accounts payable	50,288	77,453
Accrued interest and taxes	9,885	11,866
Accrued payroll related items	13,696	15,870
Regulatory liabilities - current	15,812	7,966
Other current liabilities	9,087	7,418
Total Current Liabilities	109,626	125,858
Other Credits:
Deferred income taxes	279,789	280,961
Investment tax credit - deferred	49,702	44,988
Regulatory liabilities	164,177	163,336
Accrued pension and other postretirement benefits	50,583	50,155
Asset retirement obligations	73,739	69,132
Other deferred liabilities and other	68,267	67,463
Total Other Credits	686,257	676,035
Capitalization:
Common shareholders equity	1,018,884	989,419
Noncontrolling interest	153,699	150,386
Total Equity	1,172,583	1,139,805
Long-term debt	761,274	763,697
Total Capitalization	1,933,857	1,903,502
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	$ 2,729,740	$ 2,705,395