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NDPSC (Details 2) - Electricity [Member] - NDPSC [Member] - Montana-Dakota Utilities Co. [Member] - Subsequent Event [Member] $ in Millions	Feb. 01, 2022 USD ($)
Public Utilities, General Disclosures [Line Items]
Renewable Resource Cost Adjustment Rate Tariff	$ 12.4
Public Utilities, Approved Rate Increase (Decrease), Amount	$ (2.0)

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- Definition

Renewable Resource Cost Adjustment Rate Tariff

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- Definition

Amount of public utility's approved rate increase (decrease) by regulatory agency.

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- Definition

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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