Taxes	9 Months Ended
Sep. 30, 2017
Income Tax Disclosure [Abstract]
Taxes	Taxes - MGE Energy and MGE. MGE Energy's effective income tax rate for the three months ended September 30, 2017 and 2016, was 36.9% and 36.1%, respectively. MGE's effective income tax rate for the three months ended September 30, 2017 and 2016, was 36.7% and 36.0%, respectively. For both MGE Energy and MGE, the increase in the effective tax rate is due in part to lower estimated federal tax credits. MGE Energy's effective income tax rate for the nine months ended September 30, 2017 and 2016, was 36.6% and 36.4%, respectively. MGE's effective income tax rate for the nine months ended September 30, 2017 and 2016, was 36.3% and 36.4%, respectively.

Taxes

9 Months Ended

Sep. 30, 2017

Taxes - MGE Energy and MGE.

MGE Energy's effective income tax rate for the three months ended September 30, 2017 and 2016, was 36.9% and 36.1%, respectively. MGE's effective income tax rate for the three months ended September 30, 2017 and 2016, was 36.7% and 36.0%, respectively. For both MGE Energy and MGE, the increase in the effective tax rate is due in part to lower estimated federal tax credits.

MGE Energy's effective income tax rate for the nine months ended September 30, 2017 and 2016, was 36.6% and 36.4%, respectively. MGE's effective income tax rate for the nine months ended September 30, 2017 and 2016, was 36.3% and 36.4%, respectively.