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Regulatory Matters - Conservation Improvement Program (CIP) (Details) - MPUC [Member] - USD ($) $ in Millions	Jul. 14, 2016	Jun. 30, 2016
Regulatory Matters [Line Items]
CIP Spend Requirement		1.50%
Subsequent Event [Member] | CIP Annual Filing [Member] | Minnesota Power [Member]
Regulatory Matters [Line Items]
CIP Financial Incentive	$ 7.5

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- Definition

Conservation improvement program financial incentive approved by the public utilities commission.

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- Definition

Minnesota's 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.

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No definition available.

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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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