2.4.0.8010090 - Disclosure - Basis of Presentationtruefalsefalse1false falsefalseFROM_Jan01_2013_TO_Jun30_2013http://www.sec.gov/CIK0001161728duration2013-01-01T00:00:002013-06-30T00:00:001true 1mgee_BasisOfPresentationDisclosureAbstractmgee_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Basis of Presentation Disclosure [Abstract]2false 2us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse001.       Basis of Presentation - MGE Energy and MGE.        This report is a combined report of MGE Energy and MGE. References in this report to "MGE Energy" are to MGE Energy, Inc., and its subsidiaries. References in this report to "MGE" are to Madison Gas and Electric Company.        MGE Power Elm Road and MGE Power West Campus own electric generating assets and lease those assets to MGE. Both entities are variable interest entities under applicable authoritative guidance. MGE is considered the primary beneficiary of these entities as a result of contractual agreements. As a result, MGE has consolidated MGE Power Elm Road and MGE Power West Campus. See Footnote 2 of Notes to Consolidated Financial Statements under Item 8, Financial Statements and Supplementary Data, of MGE Energy's and MGE's 2012 Annual Report on Form 10-K.        The accompanying consolidated financial statements as of June 30, 2013, and for the three and six months ended, are unaudited, but include all adjustments that MGE Energy and MGE management consider necessary for a fair statement of their respective financial statements. All adjustments are of a normal, recurring nature except as otherwise disclosed. The year-end consolidated balance sheet information was derived from the audited balance sheet appearing in MGE Energy's and MGE's 2012 Annual Report on Form 10-K, but does not include all disclosures required by accounting principles generally accepted in the United States of America. These notes should be read in conjunction with the financial statements and the notes on pages 51 through 104 of the 2012 Annual Report on Form 10-K.falsefalsefalsenonnum:textBlockItemTypenaThe entire disclosure for organization, consolidation and basis of presentation of financial statements disclosure.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Interpretation (FIN) -Number 46R -Paragraph 4, 14, 15 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. 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