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MTPSC (Details 2) - Pending Rate Case [Member] - MTPSC - Montana-Dakota Utilities Co. [Member] - Electric - USD ($)
$ in Millions
Mar. 15, 2023
Feb. 01, 2023
Nov. 04, 2022
Public Utilities, General Disclosures [Line Items]      
Public Utilities, Requested Rate Increase (Decrease), Amount     $ 10.5
Public Utilities, Requested Rate Increase (Decrease), Percentage     15.20%
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount $ 11.5    
Public Utilities, Requested Rate Increase (Decrease), Amended, Percentage 17.00%    
Public Utilities, Interim Rate Increase (Decrease), Amount   $ 1.7  
Public Utilities, Interim Rate Increase (Decrease), Percentage   2.70%