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Regulatory Environment - Natural Gas Storage Facility (Details) | 12 Months Ended
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Dec. 31, 2017
Michigan Natural Gas Storage Facility [Member] | Public Service Commission of Wisconsin (PSCW) | WE, WG, and WPS |
Public Utilities, General Disclosures [Line Items] |
Natural gas storage needs provided to Wisconsin utilities | 33.33%

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- Definition Percentage of the company's Wisconsin natural gas storage needs provided by the natural gas storage facility. + References No definition available. + Details
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- Details
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- Details
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