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Regulatory Matters - Conservation Improvement Program (Details) - MPUC [Member] - USD ($) $ in Millions | 3 Months Ended
--- | ---
Sep. 30, 2018 | Jun. 30, 2017
CIP Consolidated Filing [Member] | Minnesota Power [Member] |  |
Regulatory Matters [Line Items] |  |
Approved Financial Incentive | $ 3.0 | $ 5.5
Minimum [Member] |  |
Regulatory Matters [Line Items] |  |
CIP Spending Minimum - Percentage | 1.50% |

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- Definition Minnesota Next Generation Act of 2007 introduced a spend goal of 1.5% of net gross operating revenues from service provided in the state on energy CIPs each year. + References No definition available. + Details
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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. + References No definition available. + Details
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- Definition The amount of regulated other operating revenues recognized during the period. + References No definition available. + Details
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- Details
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- Details
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