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Commitments and Contingencies (Details-1) (USD $) In Millions, unless otherwise specified | 3 Months Ended
--- | ---
Mar. 31, 2013 MW
Air Quality Regulations [Abstract] |
Minimum capacity to be regulated by CSAPR/CAIR - MW | 25
CAIR phase one emission reductions for NOx | 55.00%
CAIR phase one emission reductions for SO2 | 40.00%
CAIR phase two emission reductions for NOx | 65.00%
CAIR phase two emission reductions for SO2 | 70.00%
Coal-fired electric generating units - MW requirement | 150
Minimum amount of fleet-wide mercury reduction in Wisconsin - Phase two | 90.00%
Columbia Clean Air Act Litigation [Abstract] |
Columbia Clean Air Act litigation civil penalties | $ 0.2
Columbia Clean Air Act litigation environmental mitigation costs | 0.6
Columbia Environmental Project [Member] |
Expected Capital Expenditures [Line Items] |
MGE's share of expected capital expenditures | 140.0
Columbia Commitments [Abstract] |
Columbia environmental project commitments | $ 56.7
Columbia Units [Member] |
Columbia Units [Line Items] |
Generating capability - MW | 225
Columbia's share of MGE's net generating capability | 29.00%
Ownership interest in jointly owned plant | 22.00%
WPL ownership interest of Columbia | 46.20%
WPSC ownership interest of Columbia | 31.80%

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- Definition The reduction of annual regional emission for NOx required under the first phase of the Clean Air Interstate Rule (CAIR). + References No definition available. + Details
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- Definition The reduction of annual regional emission for SO2 required under the first phase of the Clean Air Interstate Rule (CAIR). + References No definition available. + Details
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- Definition The reduction of annual regional emission for NOx required under the second phase (beginning in 2015) of the Clean Air Interstate Rule (CAIR). + References No definition available. + Details
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- Definition The reduction of annual regional emission for SO2 required under the second phase (beginning in 2015) of the Clean Air Interstate Rule (CAIR). + References No definition available. + Details
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- Definition A large coal-fired electric generating Unit is one that produces at least this amount of MW. + References No definition available. + Details
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- Definition This element represents the expenses incurred by the entity which are directly related to settlement of litigation. + References No definition available. + Details
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- Definition This element represents the approximate costs of environmental mitigation projects agreed to in the terms of the final consent decree. + References No definition available. + Details
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- Definition Committed Columbia environmental project commitments. + References No definition available. + Details
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- Definition Expected capital expenditures to be incurred during construction of an asset. + References No definition available. + Details
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- Definition A jointly owned utility plant's share of MGE's net generating capability. + References No definition available. + Details
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- Definition MGE's portion of the total operating capacity (in MWs) of each of the two units in the jointly owned utility plant. + References No definition available. + Details
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- Definition WPL's proportionate share of interest (percent) in Columbia, a jointly owned utility plant. + References No definition available. + Details
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- Definition WPSC's proportionate share of interest (percent) in Columbia, a jointly owned utility plant. + References No definition available. + Details
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- Definition Under phase two of the Wisconsin State Mercury Rule, beginning January 2015, large coal-fired electric generating units had to reduce mercury emissions by this minimum percent or choose a multi-pollutation reduction approach. + References No definition available. + Details
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- Definition Electric generating units in Wisconsin that meet the minimum capacity (in MWs) are regulated by U.S Cross-State Air Pollution Rule (CSAPR) and Clean Air Interstate Rule (CAIR). + References No definition available. + Details
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- Definition The proportionate share of interest (percent) in a jointly owned utility plant. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 10 -Section C Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 10.C) -URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033 + Details
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