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Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2025 | Dec. 31, 2024 | Dec. 31, 2023
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |  |
Balance at beginning of period |  | $ 9,029,742 | $ 8,098,076 | $ 8,372,840
Charged to costs and expenses | [1] | 5,850,001 | 4,850,000 | 3,264,309
Charged to other accounts |  | 51,600 | 54,000 | 20,400
Net accounts written off | [2] | (4,269,143) | (3,972,334) | (3,559,473)
Balance at end of period |  | 10,662,201 | 9,029,742 | 8,098,076
Deferred Bad Debt Expense [Member] |  |  |  |
Regulatory Asset [Line Items] |  |  |  |
Regulatory assets |  | 1,900,000 | $ 400,000 | $ 1,500,000
Collection of Bad Debt Expense [Member] |  |  |  |
Regulatory Asset [Line Items] |  |  |  |
Regulatory assets |  | $ (4,900,000) |  |
[1] | For both the years ended December 31, 2025 and 2024, MGE recovered $4.9 million of bad debt expense as a regulatory asset. For the years ended December 31, 2025, 2024, and 2023, MGE deferred $1.9 million, $0.4 million, and $1.5 million, respectively, of bad debt expense as a regulatory asset. See Footnote 8 of the Notes to Consolidated Financial Statements in this Report for further information.
[2] | Net of recovery of amounts previously written off.

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