Joint Plant Ownership	3 Months Ended
Mar. 31, 2020
Regulated Operations [Abstract]
Joint Plant Ownership	Joint Plant Ownership - MGE Energy and MGE. a. Two Creeks. In May 2019, MGE acquired a 33% ownership interest in a 150 MW solar generation array to be constructed in the Town of Two Creeks and the City of Two Rivers in Manitowoc and Kewaunee Counties, Wisconsin. MGE's sole principal asset will be the 33% undivided ownership interest in the solar generation facility that is being constructed. The estimated share of capital costs for MGE's ownership interest is approximately $65 million (excluding AFUDC). As of March 31, 2020, $44.2 million (excluding AFUDC) related to this project was reflected in "Construction work in progress" on the consolidated balance sheets. The project is anticipated to be completed by the end of 2020. MGE received specific approval to recover 100% AFUDC on the project. After tax, MGE has recognized $0.8 million in AFUDC equity related to this project for the three months ended March 31, 2020. MGE did not recognize any AFUDC equity related to this project for the three months ended March 31, 2019. b. Badger Hollow I. In July 2019, MGE acquired a 33% ownership interest in a 150 MW solar generation array to be constructed in southwestern Wisconsin in Iowa County, near the villages of Montfort and Cobb. MGE's sole principal asset will be the 33% undivided ownership interest in the solar generation facility that is being constructed. The estimated share of capital costs for MGE's ownership interest is approximately $65 million (excluding AFUDC). As of March 31, 2020, $22.3 million (excluding AFUDC) related to this project was reflected in "Construction work in progress" on the consolidated balance sheets. The project is anticipated to be completed in April 2021. MGE received specific approval to recover 100% AFUDC on the project. After tax, MGE has recognized $0.4 million in AFUDC equity related to this project for the three months ended March 31, 2020. MGE did not recognize any AFUDC equity related to this project for the three months ended March 31, 2019.

Joint Plant Ownership

3 Months Ended

Mar. 31, 2020

Joint Plant Ownership - MGE Energy and MGE.

a. Two Creeks.

In May 2019, MGE acquired a 33% ownership interest in a 150 MW solar generation array to be constructed in the Town of Two Creeks and the City of Two Rivers in Manitowoc and Kewaunee Counties, Wisconsin. MGE's sole principal asset will be the 33% undivided ownership interest in the solar generation facility that is being constructed. The estimated share of capital costs for MGE's ownership interest is approximately $65 million (excluding AFUDC).

As of March 31, 2020, $44.2 million (excluding AFUDC) related to this project was reflected in "Construction work in progress" on the consolidated balance sheets. The project is anticipated to be completed by the end of 2020. MGE received specific approval to recover 100% AFUDC on the project. After tax, MGE has recognized $0.8 million in AFUDC equity related to this project for the three months ended March 31, 2020. MGE did not recognize any AFUDC equity related to this project for the three months ended March 31, 2019.

b. Badger Hollow I.

In July 2019, MGE acquired a 33% ownership interest in a 150 MW solar generation array to be constructed in southwestern Wisconsin in Iowa County, near the villages of Montfort and Cobb. MGE's sole principal asset will be the 33% undivided ownership interest in the solar generation facility that is being constructed. The estimated share of capital costs for MGE's ownership interest is approximately $65 million (excluding AFUDC).

As of March 31, 2020, $22.3 million (excluding AFUDC) related to this project was reflected in "Construction work in progress" on the consolidated balance sheets. The project is anticipated to be completed in April 2021. MGE received specific approval to recover 100% AFUDC on the project. After tax, MGE has recognized $0.4 million in AFUDC equity related to this project for the three months ended March 31, 2020. MGE did not recognize any AFUDC equity related to this project for the three months ended March 31, 2019.