Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 14,708	$ 11,604
Accounts receivable, less reserves	52,612	55,407
Other accounts receivables, less reserves	11,667	11,418
Unbilled revenues	31,654	43,086
Materials and supplies, at average cost	34,697	33,465
Fuel for electric generation, at average cost	11,605	7,962
Stored natural gas, at average cost	23,132	32,848
Prepaid taxes	12,522	19,132
Regulatory assets - current	16,790	9,541
Other current assets	13,862	19,017
Total Current Assets	223,249	243,480
Regulatory assets	100,556	103,900
Pension benefit asset	70,591	68,872
Other deferred assets and other	22,993	24,365
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,890,784	1,865,352
Construction work in progress	106,322	105,748
Total Property, Plant, and Equipment	1,997,106	1,971,100
Investments	107,706	105,883
Total Assets	2,522,201	2,517,600
Current Liabilities:
Long-term debt due within one year	35,046	54,314
Short-term debt	33,000	70,500
Accounts payable	38,720	59,334
Accrued interest and taxes	6,482	7,868
Accrued payroll related items	9,888	13,064
Regulatory liabilities - current	17,017	11,925
Other current liabilities	5,853	8,057
Total Current Liabilities	146,006	225,062
Other Credits:
Deferred income taxes	259,180	252,190
Investment tax credit - deferred	48,260	48,735
Regulatory liabilities	153,253	156,988
Accrued pension and other postretirement benefits	53,850	53,607
Finance lease liabilities	17,286	17,108
Other deferred liabilities and other	93,192	96,990
Total Other Credits	625,021	625,618
Capitalization:
Common shareholders equity	1,098,370	1,081,674
Long-term debt	652,804	585,246
Total Capitalization	1,751,174	1,666,920
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	2,522,201	2,517,600
MGE [Member]
Current Assets:
Cash and cash equivalents	5,075	4,136
Accounts receivable, less reserves	52,612	55,407
Other accounts receivables, less reserves	11,664	11,416
Unbilled revenues	31,654	43,086
Materials and supplies, at average cost	34,697	33,465
Fuel for electric generation, at average cost	11,605	7,962
Stored natural gas, at average cost	23,132	32,848
Prepaid taxes	12,181	18,467
Regulatory assets - current	16,790	9,541
Other current assets	14,452	19,479
Total Current Assets	213,862	235,807
Regulatory assets	100,556	103,900
Pension benefit asset	70,591	68,872
Other deferred assets and other	23,280	24,817
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,890,812	1,865,380
Construction work in progress	106,322	105,748
Total Property, Plant, and Equipment	1,997,134	1,971,128
Investments	130	115
Total Assets	2,405,553	2,404,639
Current Liabilities:
Long-term debt due within one year	35,046	54,314
Short-term debt	33,000	70,500
Accounts payable	38,696	59,317
Accrued interest and taxes	6,437	7,912
Accrued payroll related items	9,888	13,064
Regulatory liabilities - current	17,017	11,925
Other current liabilities	5,852	6,062
Total Current Liabilities	145,936	223,094
Other Credits:
Deferred income taxes	225,872	219,258
Investment tax credit - deferred	48,260	48,735
Regulatory liabilities	153,253	156,988
Accrued pension and other postretirement benefits	53,850	53,607
Finance lease liabilities	17,286	17,108
Other deferred liabilities and other	94,763	98,217
Total Other Credits	593,284	593,913
Capitalization:
Common shareholders equity	865,846	854,223
Noncontrolling interest	147,683	148,163
Total Equity	1,013,529	1,002,386
Long-term debt	652,804	585,246
Total Capitalization	1,666,333	1,587,632
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	$ 2,405,553	$ 2,404,639