Amount of public utility's approved rate increase (decrease) by 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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Percentage of public utility's requested return on equity.

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The amount of regulated other operating revenues recognized during the period.

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The amount for the individual regulatory liability as itemized in a table of regulatory liabilities as of the end of the period.

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REGULATORY MATTERS - Electric Rates (Details) - USD ($) $ in Thousands						3 Months Ended	9 Months Ended
	May 03, 2024	Apr. 01, 2024	Mar. 29, 2024	Dec. 19, 2023	Nov. 01, 2023	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Regulatory Matters [Line Items]
Regulatory Assets							$ 386,100		$ 425,400
ECO Annual Filing Member \| MPUC \| Minnesota Power
Regulatory Matters [Line Items]
Revenue from cost recovery riders and other regulatory programs		$ 2,200				$ 2,200
Electric Rates \| Fuel Adjustment Clause 2023 \| MPUC \| Minnesota Power
Regulatory Matters [Line Items]
Regulatory Assets									$ 13,000
Retail Customers \| Electric Rates \| Current Cost Recovery Rider \| MPUC \| Minnesota Power
Regulatory Matters [Line Items]
Revenue from cost recovery riders and other regulatory programs							15,100	$ 44,900
Retail Customers \| Electric Rates \| 2024 Minnesota General Rate Case \| MPUC \| Minnesota Power
Regulatory Matters [Line Items]
Requested rate increase percent					12.00%
Requested return on equity	9.78%				10.30%
Requested equity capital structure					53.00%
Annual additional revenue generated from requested final rate increase	$ 33,970				$ 89,000
Approved rate increase				$ 64,000
Regulatory liabilities							$ 17,000
Retail Customers \| Electric Rates \| 2024 Wisconsin General Rate Case \| PSCW \| SWL&P
Regulatory Matters [Line Items]
Requested rate increase percent			5.90%
Requested return on equity			10.00%
Requested equity capital structure			55.00%
Annual additional revenue generated from requested final rate increase			$ 7,300