REGULATORY ENVIRONMENT - MGU 2021 RATE APPLICATION (Details) - Michigan Public Service Commission (MPSC) - MGU - USD ($) $ in Millions	Mar. 22, 2021	Jul. 01, 2020
Public Utilities, General Disclosures [Line Items]
Depreciation and interest expense approved for deferral		$ 5.0
Requested rate increase	$ 15.1
Requested rate increase (as a percent)	10.70%
Requested return on equity (as a percent)	10.20%
Requested common equity component average (as a percent)	52.50%

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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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Percentage of public utility's requested equity to capital, including debt and equity.

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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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Percentage of public utility's requested return on equity.

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Amount of depreciation and interest expense approved for deferral in 2021.

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