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	$ 97,616	93,202				76,820		16,382
Cash dividends paid to parent by MGE		(30,000)				(30,000)
Distributions to parent from noncontrolling interest		(17,250)						(17,250)
Ending balance, shares at Sep. 30, 2023			36,163	17,348
Ending balance, value at Sep. 30, 2023		1,048,338		$ 17,348	252,917	630,778	0	147,295
Beginning balance, shares at Jun. 30, 2023			36,163	17,348
Beginning balance, value at Jun. 30, 2023		1,028,386		$ 17,348	252,917	609,313	0	148,808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	37,857	35,952				30,465		5,487
Cash dividends paid to parent by MGE		(9,000)				(9,000)
Distributions to parent from noncontrolling interest		(7,000)						(7,000)
Ending balance, shares at Sep. 30, 2023			36,163	17,348
Ending balance, value at Sep. 30, 2023		1,048,338		$ 17,348	252,917	630,778	0	147,295
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	98,547	93,064				75,924		17,140
Cash dividends paid to parent by MGE		(31,000)				(31,000)
Distributions to parent from noncontrolling interest		(16,000)						(16,000)
Ending balance, shares at Sep. 30, 2024			36,205	17,348
Ending balance, value at Sep. 30, 2024		1,099,320		$ 17,348	252,917	678,384	0	150,671
Beginning balance, shares at Jun. 30, 2024			36,176	17,348
Beginning balance, value at Jun. 30, 2024		1,073,210		$ 17,348	252,917	652,051	0	150,894
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 40,939	39,110				33,333		5,777
Cash dividends paid to parent by MGE		(7,000)				(7,000)
Distributions to parent from noncontrolling interest		(6,000)						(6,000)
Ending balance, shares at Sep. 30, 2024			36,205	17,348
Ending balance, value at Sep. 30, 2024		$ 1,099,320		$ 17,348	$ 252,917	$ 678,384	$ 0	$ 150,671