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Regulatory Assets and Liabilities (Tables) | 12 Months Ended
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Dec. 31, 2025
Regulatory Assets and Liabilities Disclosure [Abstract] |
Regulatory Assets and Liabilities | The following regulatory assets and liabilities are reflected in MGE's consolidated balance sheets as of December 31:
(In thousands) |  | Recovery/Refund Period |  | 2025 |  |  | 2024 |
Regulatory Assets |  |  |  |  |  |  |  |
Asset retirement obligation |  | ARO Asset lives |  | $ | 9,592 |  |  | $ | 6,813 |
Bad debt expense |  | One to two years |  |  | 2,250 |  |  |  | 5,200 |
Debt related costs |  | Term of related debt |  | $ | 6,077 |  |  | $ | 6,538 |
Derivatives |  | One to four years |  |  | 1,595 |  |  |  | — |
Leases |  | Lease term |  |  | 5,031 |  |  |  | 4,598 |
Pension and other postretirement costs |  | One to four years |  |  | — |  |  |  | 642 |
Tax recovery related to AFUDC equity |  | Plant lives |  |  | 14,859 |  |  |  | 13,440 |
Transmission |  | One to two years |  |  | 2,258 |  |  |  | 1,216 |
West Riverside |  | One to two years |  |  | 3,453 |  |  |  | 1,276 |
Other |  | Various |  |  | 6,522 |  |  |  | 5,563 |
Total Regulatory Assets |  |  |  | $ | 51,637 |  |  | $ | 45,286 |
(In thousands) |  | Recovery/Refund Period |  | 2025 |  |  | 2024 |
Regulatory Liabilities |  |  |  |  |  |  |  |
Cost of removal |  | Various |  | $ | 46,022 |  |  | $ | 41,714 |
Elm Road |  | One to two years |  |  | 1,444 |  |  |  | 1,700 |
Fuel savings |  | One year |  |  | 7,140 |  |  |  | 3,043 |
Income taxes |  | Various |  |  | 90,963 |  |  |  | 94,110 |
Pension and other postretirement costs |  | One to four years |  |  | 4,919 |  |  |  | — |
Pension and other postretirement non-service costs |  | Plant lives |  |  | 23,115 |  |  |  | 20,342 |
Purchased gas adjustment |  | Less than one year |  |  | 4,736 |  |  |  | 1,441 |
Renewable project savings |  | One to two years |  |  | 5,407 |  |  |  | 5,222 |
Unfunded pension and other postretirement asset |  | Various |  |  | 24,019 |  |  |  | 3,489 |
Other |  | Various |  |  | 1,097 |  |  |  | 241 |
Total Regulatory Liabilities |  |  |  | $ | 208,862 |  |  | $ | 171,302 |

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- Definition Tabular disclosure of regulatory assets and liabilities. Assets are created when regulatory agencies permit public utilities to defer certain costs included in rate-setting to the balance sheet. Liabillities are the result of rate actions a regulator can impose on a regulated enterprise resulting in a regulatory liability. + References No definition available. + Details
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- References No definition available. + Details
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