2.4.0.8010270 - Disclosure - Rate Matterstruefalsefalse1false falsefalseFROM_Jan01_2013_TO_Jun30_2013http://www.sec.gov/CIK0001161728duration2013-01-01T00:00:002013-06-30T00:00:001true 1mgee_RateMattersDisclosureAbstractmgee_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Rate Matters Disclosure [Abstract]2false 2us-gaap_PublicUtilitiesDisclosureTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse0010.       Rate Matters - MGE Energy and MGE. a.       Rate Proceedings. On July 26, 2013, the PSCW authorized MGE to freeze electric and natural gas rates at 2013 levels for 2014. The order includes authorizing 100% AFUDC on the Columbia scrubber construction project and deferral of increased costs related to ATC and MISO Schedule 26 fees. As a result of the authorization, approximately $6.2 million associated with a 2012 fuel rule surplus credit will not be required to be refunded to customers and will be amortized in 2014. The fuel credit will accrue interest at MGE's weighted cost of capital. The authorized return on equity will remain unchanged at 10.3%. On December 14, 2012, the PSCW authorized MGE to increase 2013 rates for retail electric customers by 3.8% or $14.9 million and to increase gas rates by 1.0% or $1.6 million. The change in retail electric rates was driven by costs for new environmental equipment at Columbia, final construction costs for the Elm Road Units, transmission reliability enhancements, and purchased power costs. The authorized return on common stock equity remains unchanged at 10.3%. On December 15, 2011, under a limited reopener of MGE's last rate order, the PSCW authorized MGE to increase 2012 rates for retail electric customers by 4.3% or $15.7 million and to increase gas rates by 0.3% or $0.6 million. The change in retail electric rates was driven by MGE's electric fuel and purchased power costs, increased transmission costs, an update to the Elm Road Units' costs, and an increase for energy efficiency programs. The PSCW also approved deferral of CSAPR costs.b.       Fuel Rules. Fuel rules require the PSCW and Wisconsin utilities to defer electric fuel-related costs that fall outside a symmetrical cost tolerance band around the amount approved for a utility in its most recent base rate proceedings. Any over/under recovery of the actual costs is determined on an annual basis and will be adjusted in future billings to electric retail customers. The fuel rules bandwidth is currently set at plus or minus 2%. Under fuel rules, MGE would defer costs, less any excess revenues, if its actual electric fuel costs exceeded 102% of the electric fuel costs allowed in its latest rate order. Excess revenues are defined as revenues in the year in question that provide MGE with a greater return on common equity than authorized by the PSCW in MGE's latest rate order. Conversely, MGE is required to defer the benefit of lower costs if actual electric fuel costs were less than 98% of the electric fuel costs allowed in that order. As of June 30, 2013, MGE has deferred $0.4 million (to be returned to customers in a future period) of 2013 electric fuel-related savings that are outside the range authorized by the PSCW.falsefalsefalsenonnum:textBlockItemTypenaThe entire disclosure for public utilities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 71 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Rate MattersfalseRate MattersUnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.mgeenergy.com/role/DisclosureRateMatters12