This item represents disclosure of the amount of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporation; these investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities.

+ References+ Details

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6382870&loc=d3e33749-111570

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 19

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 6

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

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-Article 7

Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 5

-Section 03

-Paragraph 9

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.12)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

+ Details

- Definition

Describes the event or transaction that occurred between the balance sheet date and the date the financial statements are issued or available to be issued.

+ References+ Details

Investment in ATC (Details-1) (USD $)	3 Months Ended		4 Months Ended			3 Months Ended
Investment in ATC (Details-1) (USD $)	Mar. 31, 2013	Mar. 31, 2012	Apr. 30, 2013 Mge Transco [Member] ATC Capital Contribution [Member]	Mar. 31, 2013 ATC [Member]	Dec. 31, 2012 ATC [Member]	Mar. 31, 2013 ATC [Member] Mge Transco [Member]	Mar. 31, 2012 ATC [Member] Mge Transco [Member]
Equity method investments [Line Items]
Equity earnings from investment in ATC	$ 2,396,000	$ 2,242,000				$ 2,400,000	$ 2,200,000
Dividend income from ATC	1,807,000	1,740,000				1,800,000	1,700,000
Contributions to ATC						200,000	400,000
Investment in ATC				61,800,000	61,000,000
Subsequent Events [Line Items]
Subsequent Event, Description			On April 30, 2013, MGE Transco made a $0.5 million capital contribution to ATC.
Contributions to ATC	$ 373,000	$ 355,000	$ 500,000