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Regulatory matters - NDPSC (Details) - Natural gas distribution - NDPSC - Montana-Dakota Utilities Co. - Pending Rate Case - USD ($) $ in Millions | Dec. 13, 2023 | Nov. 01, 2023
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Public Utilities, General Disclosures [Line Items] |  |
Public utilities, requested rate increase (decrease), amount |  | $ 11.6
Public utilities, requested rate increase (decrease), percentage |  | 7.50%
Public utilities, interim rate increase (decrease), amount | $ 10.1 |
Public utilities, interim rate increase (decrease), percentage | 6.50% |

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