XML 114 R92.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Commitments and Contingencies (Details-3) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2015 USD ($) Tons ppb pollutant phase state MW
Columbia Environmental Project, SCR [Member] | MGE [Member] |
Columbia |
Share of projected SCR project cost, minimum | $ | $ 19
Share of projected SCR project cost, maximum | $ | $ 29
Wisconsin Energy Efficiency and Renewables Act [Member] |
Energy Efficiency and Renewables |
Minimum electricity generated from renewable resources by 2015 | 10.00%
EPA [Member] |
Effluent Limitations Guidelines and Standards for Steam Electric Power Generating Source Category [Abstract] |
Air pollution control and ash handling systems capacity at coal burning power plants, minimum (in MW) | MW | 50
EPA's Greenhouse Gas Reduction Guidelines |
National average reduction of greenhouse gas emissions by the year 2030, percentage | 32.00%
Compliance plan preparation term related to the greenhouse gas emissions reduction guidelines | 3 years
EPA's National Ambient Air Quality Standards |
Number of pollutants monitored by the National Ambient Air Quality Standards | pollutant | 6
EPA's Ozone NAAQS |
Current primary regulated level of Ozone NAAQS (in parts per billion) | ppb | 70
Current secondary regulated level of Ozone NAAQS (in parts per billion) | ppb | 70
EPA's Sulfur Dioxide NAAQS |
Annual maximum level of sulfur dioxide for large stationary sources | Tons | 2,000
Number of phases for for attainment and nonattainment area designation | phase | 3
EPA's Cross State Air Pollution Rule |
Number of eastern states identified contributing to pollution in other states | state | 27
Number of phases for allocation of NOx and SO2 allowances to qualifying power plants under the rule | phase | 2
Number of states incorporating 2008 ozone NAAQS attainment levels | state | 23

X
- References No definition available. + Details
Name: | mgee_ColumbiaCommitmentsAbstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | mgee_Effluentlimitationsguidelinesandstandardsforsteamelectricpowergeneratingsourcecategoryabstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | mgee_EnergyEfficiencyAndRenewablesAbstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | mgee_EpasCrossStateAirPollutionRuleAbstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | mgee_EpasGreenhouseGasReductionGuidelinesAbstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | mgee_NationalAmbientAirQualityStandardsAbstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | mgee_Ozonenationalambientairqualitystandardsabstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of eastern states identified by the EPA's Cross State Air Pollution Rule that are contributing to pollution in other states. + References No definition available. + Details
Name: | mgee_PublicUtilitiesCrossStateAirPollutionRuleNumberOfEasternStatesContributingToPollutionInOtherStates
Namespace Prefix: | mgee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of phases for allocation of nitrogen oxide and sulfur dioxide allowances to qualifying power plants under the EPA's Cross State Air Pollution Rule. + References No definition available. + Details
Name: | mgee_PublicUtilitiesCrossStateAirPollutionRuleNumberOfPhasesForAllocationOfNitrogenOxideAndSulfurDioxideAllowancesToQualifyingPowerPlants
Namespace Prefix: | mgee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The term allowed for preparation of the compliance plan for the national average of greenhouse gas emissions required by the year 2030 for electric generating units. + References No definition available. + Details
Name: | mgee_PublicUtilitiesGreenhouseGasEmissionsReductionGuidelinesCompliancePlanPreparationTerm
Namespace Prefix: | mgee_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage reduction of the national average of greenhouse gas emissions required by the year 2030 for electric generating units. + References No definition available. + Details
Name: | mgee_PublicUtilitiesGreenhouseGasEmissionsReductionGuidelinesNationalAverageReductionRequirementBy2030Percentage
Namespace Prefix: | mgee_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The minimum electricity generated from renewable resources by 2015 set by regulatory agency + References No definition available. + Details
Name: | mgee_PublicUtilitiesMinimumElectricityGeneratedFromRenewableResourcesBy2015
Namespace Prefix: | mgee_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of pollutants monitored by the National Ambient Air Quality Standards. + References No definition available. + Details
Name: | mgee_PublicUtilitiesNationalAmbientAirQualityStandardsNumberOfPollutantsMonitored
Namespace Prefix: | mgee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The Company's maximum share of the projected SCR project cost under the Columbia Clean Air Act. + References No definition available. + Details
Name: | mgee_Publicutilitiescolumbiacleanairactlitigationshareofprojectedprojectcostmaximum
Namespace Prefix: | mgee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The Company's minimum share of the projected SCR project cost under the Columbia Clean Air Act. + References No definition available. + Details
Name: | mgee_Publicutilitiescolumbiacleanairactlitigationshareofprojectedprojectcostminimum
Namespace Prefix: | mgee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The number of states identified by the EPA's Cross State Air Pollution Rule that are subject to the proposed amendment which incorporate 2008 Ozone NAAQS levels. + References No definition available. + Details
Name: | mgee_Publicutilitiescrossstateairpollutionrulenumberofstatesincorporating2008ozonenaaqsattainmentlevels
Namespace Prefix: | mgee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The air pollution control and ash handling systems capacity minimum as required by the Effluent Limitations Guidelines. + References No definition available. + Details
Name: | mgee_Publicutilitieseffluentlimitationsguidelinesairpollutioncontrolandashhandlingsystemscapacityminimum
Namespace Prefix: | mgee_
Data Type: | num:powerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The annual maximum level of sulfur dioxide emissions for large stationary sources. + References No definition available. + Details
Name: | mgee_Publicutilitiesmaximumannualsulfurdioxideemissionsforlargestationarysources
Namespace Prefix: | mgee_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition The current primary regulated level of Ozone NAAQS by the National Ambient Air Quality Standards. + References No definition available. + Details
Name: | mgee_Publicutilitiesnationalambientairqualitystandardscurrentprimaryregulatedozonenaaqslevel
Namespace Prefix: | mgee_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition The current secondary regulated level of Ozone NAAQS by the National Ambient Air Quality Standards. + References No definition available. + Details
Name: | mgee_Publicutilitiesnationalambientairqualitystandardscurrentsecondaryregulatedozonenaaqslevel
Namespace Prefix: | mgee_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of phases for attainment and nonattainment area designation under the EPA's Sulfur Dioxide NAAQS. + References No definition available. + Details
Name: | mgee_Publicutilitiessulfurdioxidenaaqsnumberofphasesforattainmentnonattainmentareadesignations
Namespace Prefix: | mgee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | mgee_Sulfurdioxidenationalambientairqualitystandardsabstract
Namespace Prefix: | mgee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | mgee_ConstructionProjectAxis=mgee_ColumbiaEnvironmentalProjectSCRMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=us-gaap_SubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=mgee_WisconsinEnergyEfficiencyAndRenewablesActMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=mgee_UnitedStatesEnvironmentalProtectionAgencyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |