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, 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
Beginning balance, shares at Dec. 31, 2024			36,490	17,348
Beginning balance, value at Dec. 31, 2024		1,139,805		$ 17,348	283,667	688,404	0	150,386
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 41,592	39,803				34,204		5,599
Cash dividends paid to parent by MGE		(13,500)				(13,500)
Distributions to parent from noncontrolling interest		(4,000)						(4,000)
Ending balance, shares at Mar. 31, 2025			36,537	17,348
Ending balance, value at Mar. 31, 2025		$ 1,162,108		$ 17,348	$ 283,667	$ 709,108	$ 0	$ 151,985