Madison Gas and Electric Company Consolidated Statements of Common Equity (Unaudited) - USD ($) shares in Thousands, $ 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 Income/(Loss) [Member] MGE [Member]	Noncontrolling Interest [Member] MGE [Member]
Beginning balance, shares at Dec. 31, 2022			36,163	17,348
Beginning 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	$ 31,078	29,643				24,123		5,520
Cash dividends paid to parent by MGE		(12,500)				(12,500)
Distributions to parent from noncontrolling interest		(6,000)						(6,000)
Ending balance, shares at Mar. 31, 2023			36,163	17,348
Ending balance, value at Mar. 31, 2023		1,013,529		$ 17,348	252,917	595,581	0	147,683
Beginning balance, shares at Dec. 31, 2023			36,163	17,348
Beginning balance, value at Dec. 31, 2023		1,053,256		$ 17,348	252,917	633,460	0	149,531
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 33,814	32,200				26,603		5,597
Cash dividends paid to parent by MGE		(14,000)				(14,000)
Distributions to parent from noncontrolling interest		(4,000)						(4,000)
Ending balance, shares at Mar. 31, 2024			36,176	17,348
Ending balance, value at Mar. 31, 2024		$ 1,067,456		$ 17,348	$ 252,917	$ 646,063	$ 0	$ 151,128