FERC (Details 6) $ in Millions	Jan. 01, 2021 USD ($)
MISO [Member] \| Montana-Dakota Utilities Co. [Member] \| Electric \| Subsequent Event [Member]
Public Utilities, General Disclosures [Line Items]
Transmission Formula Revenue Requirement	$ 12.9

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.

No definition available.

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