Madison Gas and Electric Company Consolidated Statements of Equity - USD ($) $ in Thousands	Total	MGE [Member]	Common Stock [Member]	Common Stock [Member] MGE [Member]	Additional Paid-in Capital [Member] MGE [Member]	Retained Earnings [Member] MGE [Member]	Accumulated Other Comprehensive (Loss)/ Income [Member] MGE [Member]	Noncontrolling Interest [Member] MGE [Member]
Beginning balance, shares at Dec. 31, 2020			36,163,000	17,348,000
Beginning balance, value at Dec. 31, 2020		$ 871,612		$ 17,348	$ 252,917	$ 460,151	$ 0	$ 141,196
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 105,761	100,782				78,391		22,391
Cash dividends paid to parent by MGE		(5,000)				(5,000)
Distributions to parent from noncontrolling interest		(15,000)						(15,000)
Ending balance, shares at Dec. 31, 2021			36,163,000	17,348,000
Ending balance, value at Dec. 31, 2021		952,394		$ 17,348	252,917	533,542	0	148,587
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	110,952	105,492				83,916		21,576
Cash dividends paid to parent by MGE		(33,500)				(33,500)
Distributions to parent from noncontrolling interest		(22,000)						(22,000)
Ending balance, shares at Dec. 31, 2022			36,163,000	17,348,000
Ending balance, value at Dec. 31, 2022		1,002,386		$ 17,348	252,917	583,958	0	148,163
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 117,699	112,370				90,502		21,868
Cash dividends paid to parent by MGE		(41,000)				(41,000)
Distributions to parent from noncontrolling interest		(20,500)						(20,500)
Ending balance, shares at Dec. 31, 2023			36,163,000	17,348,000
Ending balance, value at Dec. 31, 2023		$ 1,053,256		$ 17,348	$ 252,917	$ 633,460	$ 0	$ 149,531