Rate Matters	9 Months Ended
Rate Matters	Sep. 30, 2014
Regulated Operations [Abstract]
Rate Matters	Rate Matters - MGE Energy and MGE. a. Rate Proceedings. On April 17, 2014, MGE filed an application with the PSCW requesting a 2.8% increase to electric rates and a 2.3% decrease to gas rates for 2015. MGE has requested escrow accounting treatment for transmission related costs starting in 2015. This treatment will allow MGE to reflect any differential between costs reflected in rates and actual costs incurred in its next rate case filing. The proposed electric rate increases cover costs associated with the construction of emission-reduction equipment at Columbia and improvements and reliability of the state's electric transmission system. During the rate case proceeding, certain updates have been made to reflect changing conditions from the initial filing. Those updates include increased costs for fuel and purchased power costs primarily related to coal delivery costs, lower transmission costs due to favorable FERC decisions on cost allocations for system reliability payments, and increased costs to reflect current market conditions for pension and post-retirement benefit costs. Incorporating the revisions would adjust the electric rate increase from 2.8% to 4.3% and adjust the gas rate decrease from 2.3% to 1.4%. A PSCW decision is expected by the end of 2014. 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 part of the rate freeze plan authorized by the PSCW, effective January 1, 2014, 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 remained 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 remained unchanged at 10.3%. 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 September 30, 2014, MGE did not defer any 2014 electric fuel-related savings/costs that are outside the range authorized by the PSCW. As part of the rate freeze plan authorized by the PSCW for 2014, $4.7 million of the approximately $6.2 million associated with the 2012 fuel rule surplus credit was amortized against purchased power expense during the nine months ended September 30, 2014. The 2013 fuel rule surplus credit of $6.7 million was returned to customers in October 2014.