Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents		$ 11,140	$ 11,604
Accounts receivable, less reserves		46,734	55,407
Other accounts receivables, less reserves		15,618	11,418
Unbilled revenues		33,181	43,086
Materials and supplies, at average cost		33,385	33,465
Fuel for electric generation, at average cost		13,423	7,962
Stored natural gas, at average cost		25,840	32,848
Prepaid taxes		22,310	19,132
Regulatory asset - current		20,979	9,541
Other current assets		15,587	19,017
Total Current Assets		238,197	243,480
Regulatory assets		81,589	103,900
Pension and other postretirement benefit asset		93,896	68,872
Other deferred assets and other		20,741	24,365
Property, Plant, and Equipment:
Property, plant and equipment, net		2,018,121	1,865,352
Construction work in progress		110,091	105,748
Total Property, Plant, and Equipment		2,128,212	1,971,100
Investments		112,823	105,883
Total Assets		2,675,458	2,517,600
Current Liabilities:
Long-term debt due within one year		5,146	54,314
Short-term debt	[1]	38,000	70,500
Accounts payable		65,451	59,334
Accrued interest and taxes		9,372	7,868
Accrued payroll related items		15,888	13,064
Regulatory liabilities - current		15,296	11,925
Other current liabilities		8,003	8,057
Total Current Liabilities		157,156	225,062
Other Credits:
Deferred income taxes		279,029	252,190
Investment tax credit - deferred		46,892	48,735
Regulatory liabilities		162,316	156,988
Accrued pension and other postretirement benefits		55,058	53,607
Asset Retirement Obligations		54,430	50,260
Finance lease liabilities		18,039	17,108
Other deferred liabilities and other		43,643	46,730
Total Other Credits		659,407	625,618
Common shareholders' equity:
Common stock		36,163	36,163
Additional paid-in capital		396,750	395,657
Retained earnings		707,160	649,854
Total Common Shareholders' Equity		1,140,073	1,081,674
Long-term debt		718,822	585,246
Total Capitalization		1,858,895	1,666,920
Commitments and contingencies (see Footnote 16)
Total Liabilities and Capitalization		2,675,458	2,517,600
MGE [Member]
Current Assets:
Cash and cash equivalents		2,819	4,136
Accounts receivable, less reserves		46,734	55,407
Other accounts receivables, less reserves		15,616	11,416
Unbilled revenues		33,181	43,086
Materials and supplies, at average cost		33,385	33,465
Fuel for electric generation, at average cost		13,423	7,962
Stored natural gas, at average cost		25,840	32,848
Prepaid taxes		22,338	18,467
Regulatory asset - current		20,979	9,541
Other current assets		16,088	19,479
Total Current Assets		230,403	235,807
Regulatory assets		81,589	103,900
Pension and other postretirement benefit asset		93,896	68,872
Other deferred assets and other		20,780	24,817
Property, Plant, and Equipment:
Property, plant and equipment, net		2,018,149	1,865,380
Construction work in progress		110,091	105,748
Total Property, Plant, and Equipment		2,128,240	1,971,128
Investments		60	115
Total Assets		2,554,968	2,404,639
Current Liabilities:
Long-term debt due within one year		5,146	54,314
Short-term debt		38,000	70,500
Accounts payable		65,434	59,317
Accrued interest and taxes		9,325	7,912
Accrued payroll related items		15,888	13,064
Regulatory liabilities - current		15,296	11,925
Other current liabilities		6,502	6,062
Total Current Liabilities		155,591	223,094
Other Credits:
Deferred income taxes		244,634	219,258
Investment tax credit - deferred		46,892	48,735
Regulatory liabilities		162,316	156,988
Accrued pension and other postretirement benefits		55,058	53,607
Asset Retirement Obligations		54,430	50,260
Finance lease liabilities		18,039	17,108
Other deferred liabilities and other		45,930	47,957
Total Other Credits		627,299	593,913
Common shareholders' equity:
Common stock		17,348	17,348
Additional paid-in capital		252,917	252,917
Retained earnings		633,460	583,958
Total Common Shareholders' Equity		903,725	854,223
Noncontrolling interest		149,531	148,163
Total Equity		1,053,256	1,002,386
Long-term debt		718,822	585,246
Total Capitalization		1,772,078	1,587,632
Commitments and contingencies (see Footnote 16)
Total Liabilities and Capitalization		$ 2,554,968	$ 2,404,639

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