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NDPSC (Details 2) - NDPSC [Member] - Montana-Dakota Utilities Co. [Member] - USD ($) $ in Millions | Nov. 01, 2023 | Aug. 25, 2023 | Jul. 14, 2023
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Electric |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Public Utilities, Requested Rate Increase (Decrease), Amount |  |  | $ (10.7)
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount |  | $ 1.3 |
Total Transmission Cost Adjustment Rider |  |  | 2.2
Public Utilities, Requested Rate (Decrease), Net Benefit Amount |  |  | $ (7.6)
Electric | Subsequent Event [Member] | Pending Rate Case [Member] |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |
Public Utilities, Requested Rate Increase (Decrease), Amount | $ 5.7 |  |
Renewable Resource Cost Adjustment Rate Tariff | 21.0 |  |
Natural gas distribution | Subsequent Event [Member] | Pending Rate Case [Member] |  |  |
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 |  |

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