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Noncontrolling Interest (Tables) - MGE [Member] | 12 Months Ended
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Dec. 31, 2019
Noncontrolling Interest [Line Items] |
Noncontrolling Interest in Balance Sheet | The noncontrolling interest on MGE's consolidated balance sheets as of December 31 was as follows:
| (In thousands) |  | 2019 |  | 2018 |
| MGE Power Elm Road(a) | $ | 97,172 | $ | 97,519 |
| MGE Power West Campus(a) |  | 43,131 |  | 43,935 |
| Total Noncontrolling Interest | $ | 140,303 | $ | 141,454 |
Net Income Attributable to Noncontrolling Interest, Net of Tax | The net income attributable to noncontrolling interest, net of tax, for the years ended December 31, 2019, 2018, and 2017 was as follows:
| (In thousands) |  | 2019 |  | 2018 |  | 2017 |
| MGE Power Elm Road(a) | $ | 15,153 | $ | 15,384 | $ | 29,274 |
| MGE Power West Campus(a) |  | 7,196 |  | 7,168 |  | 13,963 |
| Net Income Attributable to Noncontrolling Interest, Net of Tax | $ | 22,349 | $ | 22,552 | $ | 43,237 |
(a)MGE Power Elm Road and MGE Power West Campus are not subsidiaries of MGE; however, they have been consolidated in the consolidated financial statements of MGE (see Footnote 3). MGE Power Elm Road and MGE Power West Campus are 100% owned by MGE Power, and MGE Power is 100% owned by MGE Energy. MGE Energy's proportionate share of the equity and net income (through its wholly owned subsidiary MGE Power) of MGE Power Elm Road and MGE Power West Campus is classified within the MGE consolidated financial statements as noncontrolling interest. In 2017, there was a $14.8 million and $6.8 million one-time tax impact as a result of the Tax Act for MGE Power Elm Road and MGE Power West Campus, respectively. The Tax Act reduced the federal tax rate from 35% to 21%.

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