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Regulatory Matters - Narrative (Details) - Minnesota Rate Case - MPUC - USD ($) $ in Millions |  | 1 Months Ended | 3 Months Ended
--- | --- | --- | ---
Dec. 03, 2020 | Feb. 28, 2022 | Jun. 30, 2022
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |
Revenue, approved rate increase, amount | $ 6.9 |  | $ 4.1
Revenue, approved rate increase, percent | 3.20% |  |
Revenue requirement amount |  | $ 209.0 |
Approved return on base rate, percent |  | 7.18% |
Approved return on equity, percent |  | 9.48% |
Approved equity ratio, percent |  | 52.50% |
Recovery period |  | 5 years |
Approved cap of annual base revenues, percent |  | 4.00% |

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