WYPSC (Details 5) - Distribution - Montana-Dakota Utilities Co. [Member] - Pending Rate Case [Member] - WYPSC [Member] - USD ($)	Dec. 17, 2019	May 23, 2019
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount		$ 1,100,000
Public Utilities, Requested Rate Increase (Decrease), Percentage		7.00%
Public Utilities, Requested Rate Increase (Decrease), Amended, Amount	$ 830,000
Public Utilities, Requested Rate Increase (Decrease), Amended, Percentage	5.50%

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Amount of public utility's amended requested rate increase (decrease) with regulatory agency.

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Percentage of public utility's amended requested rate increase (decrease) with regulatory agency.

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Amount of public utility's requested rate increase (decrease) with regulatory agency.

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Percentage of public utility's requested rate increase (decrease) with regulatory agency.

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