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Regulatory Matters - Narrative (Details) - Minnesota Rate Case - MPUC - USD ($) $ in Millions |  |  | 3 Months Ended
--- | --- | --- | ---
Feb. 01, 2022 | Dec. 03, 2020 | Sep. 30, 2022 | Jun. 30, 2022
Schedule of Regulatory Assets and Liabilities [Line Items] |  |  |  |
Revenue, approved rate increase, amount |  | $ 6.9 | $ 15.3 | $ 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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