SDPUC (Details 4) - SDPUC - Electricity [Member] - Montana-Dakota Utilities Co. [Member] $ in Millions	Jun. 01, 2022 USD ($)
Public Utilities, General Disclosures [Line Items]
Total Transmission Cost Adjustment Rider	$ 2.5
Transmission Capital Projects Increase (Decrease)	$ 1.5

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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