Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 31, 2025	Dec. 31, 2024
Current Assets:
Cash and cash equivalents		$ 5,666	$ 21,302
Accounts receivable, less reserves		57,558	51,277
Other accounts receivables, less reserves		12,983	10,067
Unbilled revenues		42,770	35,833
Materials and supplies, at average cost		37,850	36,187
Fuel for electric generation, at average cost		11,010	11,521
Stored natural gas, at average cost		15,317	19,937
Prepaid taxes		19,314	18,390
Regulatory asset - current		8,879	8,522
Other current assets		17,201	14,229
Total Current Assets		228,548	227,265
Regulatory assets		42,758	36,764
Pension and other postretirement benefit asset		164,985	132,264
Other deferred assets and other		18,348	26,285
Property, Plant, and Equipment:
Property, plant and equipment, net		2,279,899	2,149,138
Construction work in progress		292,969	138,208
Total Property, Plant, and Equipment		2,572,868	2,287,346
Investments		127,913	118,035
Total Assets		3,155,420	2,827,959
Current Liabilities:
Long-term debt due within one year		21,633	5,285
Short-term debt	[1]	94,527	0
Accounts payable		117,673	77,466
Accrued interest and taxes		10,269	11,558
Accrued payroll related items		17,244	15,870
Regulatory liabilities - current		23,490	7,966
Other current liabilities		11,873	7,418
Total Current Liabilities		296,709	125,563
Other Credits:
Deferred income taxes		337,798	316,397
Investment tax credit - deferred		48,609	44,988
Regulatory liabilities		185,372	163,336
Accrued pension and other postretirement benefits		51,105	50,155
Asset Retirement Obligations		76,289	69,132
Other deferred liabilities and other		63,397	64,553
Total Other Credits		762,570	708,561
Common shareholders' equity:
Common stock		36,542	36,490
Additional paid-in capital		434,959	429,515
Retained earnings		832,435	764,133
Total Common Shareholders' Equity		1,303,936	1,230,138
Long-term debt		792,205	763,697
Total Capitalization		2,096,141	1,993,835
Commitments and contingencies (see Footnote 16)
Total Liabilities and Capitalization		3,155,420	2,827,959
MGE [Member]
Current Assets:
Cash and cash equivalents		2,248	16,865
Accounts receivable, less reserves		57,558	51,277
Other accounts receivables, less reserves		12,979	10,063
Unbilled revenues		42,770	35,833
Materials and supplies, at average cost		37,850	36,187
Fuel for electric generation, at average cost		11,010	11,521
Stored natural gas, at average cost		15,317	19,937
Prepaid taxes		18,748	18,359
Regulatory asset - current		8,879	8,522
Other current assets		17,225	14,740
Total Current Assets		224,584	223,304
Regulatory assets		42,758	36,764
Pension and other postretirement benefit asset		164,985	132,264
Other deferred assets and other		17,817	25,690
Property, Plant, and Equipment:
Property, plant and equipment, net		2,279,927	2,149,165
Construction work in progress		292,969	138,208
Total Property, Plant, and Equipment		2,572,896	2,287,373
Total Assets		3,023,040	2,705,395
Current Liabilities:
Long-term debt due within one year		21,633	5,285
Short-term debt		94,527	0
Accounts payable		117,658	77,453
Accrued interest and taxes		10,234	11,866
Accrued payroll related items		17,244	15,870
Regulatory liabilities - current		23,490	7,966
Other current liabilities		8,843	7,418
Total Current Liabilities		293,629	125,858
Other Credits:
Deferred income taxes		301,198	280,961
Investment tax credit - deferred		48,609	44,988
Regulatory liabilities		185,372	163,336
Accrued pension and other postretirement benefits		51,105	50,155
Asset Retirement Obligations		76,289	69,132
Other deferred liabilities and other		67,281	67,463
Total Other Credits		729,854	676,035
Common shareholders' equity:
Common stock		17,348	17,348
Additional paid-in capital		292,167	283,667
Retained earnings		741,049	688,404
Total Common Shareholders' Equity		1,050,564	989,419
Noncontrolling interest		156,788	150,386
Total Equity		1,207,352	1,139,805
Long-term debt		792,205	763,697
Total Capitalization		1,999,557	1,903,502
Commitments and contingencies (see Footnote 16)
Total Liabilities and Capitalization		$ 3,023,040	$ 2,705,395

[1] MGE Energy short-term borrowings include MGE Energy and MGE lines of credit and MGE commercial paper.