Consolidated Balance Sheets - USD ($) $ in Thousands		Dec. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents		$ 11,604	$ 17,438
Accounts receivable, less reserves		55,407	46,205
Other accounts receivables, less reserves		11,418	16,094
Unbilled revenues		43,086	34,812
Materials and supplies, at average cost		33,465	29,863
Fuel for electric generation, at average cost		7,962	6,429
Stored natural gas, at average cost		32,848	15,668
Prepaid taxes		19,132	20,214
Regulatory asset - current		9,541	1,465
Other current assets		19,017	11,183
Total Current Assets		243,480	199,371
Other long-term receivables		556	1,155
Regulatory assets		103,900	107,547
Pension and other postretirement benefit asset		68,872	58,757
Other deferred assets and other		23,809	27,548
Property, Plant, and Equipment:
Property, plant and equipment, net		1,865,352	1,828,171
Construction work in progress		105,748	50,603
Total Property, Plant, and Equipment		1,971,100	1,878,774
Investments		105,883	98,754
Total Assets		2,517,600	2,371,906
Current Liabilities:
Long-term debt due within one year		54,314	4,889
Short-term debt	[1]	70,500	5,500
Accounts payable		59,334	64,149
Accrued interest and taxes		7,868	10,385
Accrued payroll related items		13,064	12,951
Regulatory liabilities - current		11,925	9,365
Other current liabilities		8,057	10,608
Total Current Liabilities		225,062	117,847
Other Credits:
Deferred income taxes		252,190	231,149
Investment tax credit - deferred		48,735	44,836
Regulatory liabilities		156,988	154,298
Accrued pension and other postretirement benefits		53,607	73,085
Finance lease liabilities		17,108	17,322
Other deferred liabilities and other		96,990	91,690
Total Other Credits		625,618	612,380
Common shareholders' equity:
Common stock		36,163	36,163
Additional paid-in capital		395,657	394,903
Retained earnings		649,854	596,402
Total Common Shareholders' Equity		1,081,674	1,027,468
Long-term debt		585,246	614,211
Total Capitalization		1,666,920	1,641,679
Commitments and contingencies (see Footnote 16)
Total Liabilities and Capitalization		2,517,600	2,371,906
MGE [Member]
Current Assets:
Cash and cash equivalents		4,136	6,401
Accounts receivable, less reserves		55,407	46,205
Other accounts receivables, less reserves		11,416	16,092
Unbilled revenues		43,086	34,812
Materials and supplies, at average cost		33,465	29,863
Fuel for electric generation, at average cost		7,962	6,429
Stored natural gas, at average cost		32,848	15,668
Prepaid taxes		18,467	19,379
Regulatory asset - current		9,541	1,465
Other current assets		19,479	11,629
Total Current Assets		235,807	187,943
Affiliate receivable long-term		1,059	1,589
Regulatory assets		103,900	107,547
Pension and other postretirement benefit asset		68,872	58,757
Other deferred assets and other		23,758	27,907
Property, Plant, and Equipment:
Property, plant and equipment, net		1,865,380	1,828,199
Construction work in progress		105,748	50,603
Total Property, Plant, and Equipment		1,971,128	1,878,802
Investments		115	230
Total Assets		2,404,639	2,262,775
Current Liabilities:
Long-term debt due within one year		54,314	4,889
Short-term debt		70,500	5,500
Accounts payable		59,317	64,130
Accrued interest and taxes		7,912	10,649
Accrued payroll related items		13,064	12,951
Regulatory liabilities - current		11,925	9,365
Other current liabilities		6,062	8,108
Total Current Liabilities		223,094	115,592
Other Credits:
Deferred income taxes		219,258	198,885
Investment tax credit - deferred		48,735	44,836
Regulatory liabilities		156,988	154,298
Accrued pension and other postretirement benefits		53,607	73,085
Finance lease liabilities		17,108	17,322
Other deferred liabilities and other		98,217	92,152
Total Other Credits		593,913	580,578
Common shareholders' equity:
Common stock		17,348	17,348
Additional paid-in capital		252,917	252,917
Retained earnings		583,958	533,542
Total Common Shareholders' Equity		854,223	803,807
Noncontrolling interest		148,163	148,587
Total Equity		1,002,386	952,394
Long-term debt		585,246	614,211
Total Capitalization		1,587,632	1,566,605
Commitments and contingencies (see Footnote 16)
Total Liabilities and Capitalization		$ 2,404,639	$ 2,262,775

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