Subsequent Events	9 Months Ended
Sep. 30, 2011
Subsequent Events Disclosure [Abstract]
Subsequent Events	16. Subsequent Events - MGE Energy and MGE. Receivable – Margin Account. MGE enters into financial transactions to hedge its costs for fuel used in electric generation, purchased power, and cost of gas sold to customers. These transactions are conducted pursuant to a PSCW approved risk management plan through an account held at MF Global. As of October 31, 2011, MGE had approximately $3.3 million in a customer segregated margin account held at MF Global. As a result of a bankruptcy filing on October 31, 2011 by affiliated MF Global entities, the Chicago Mercantile Exchange froze all MF Global-related accounts (including MGE's account). At this time, MGE is unable to predict the ultimate impact of these events, including any regulatory recovery related to any losses we may incur.

Tabular disclosure of significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, losses resulting from fire or flood, losses on receivables, significant realized and unrealized gains and losses that result from changes in quoted market prices of securities, declines in market prices of inventory, changes in authorized or issued debt (SEC), significant foreign exchange rate changes, substantial loans to insiders or affiliates, significant long-term investments, and substantial dividends not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 11

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Topic 855

-SubTopic 10

-Section 50

-Paragraph 2

-Name Accounting Standards Codification

-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

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