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	$ 59,759	57,250				46,355		10,895
Cash dividends paid to parent by MGE		(21,000)				(21,000)
Distributions to parent from noncontrolling interest		(10,250)						(10,250)
Ending balance, shares at Jun. 30, 2023			36,163	17,348
Ending balance, value at Jun. 30, 2023		1,028,386		$ 17,348	252,917	609,313	0	148,808
Beginning balance, shares at Mar. 31, 2023			36,163	17,348
Beginning balance, value at Mar. 31, 2023		1,013,529		$ 17,348	252,917	595,581	0	147,683
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	28,681	27,607				22,232		5,375
Cash dividends paid to parent by MGE		(8,500)				(8,500)
Distributions to parent from noncontrolling interest		(4,250)						(4,250)
Ending balance, shares at Jun. 30, 2023			36,163	17,348
Ending balance, value at Jun. 30, 2023		1,028,386		$ 17,348	252,917	609,313	0	148,808
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	57,608	53,954				42,591		11,363
Cash dividends paid to parent by MGE		(24,000)				(24,000)
Distributions to parent from noncontrolling interest		(10,000)						(10,000)
Ending balance, shares at Jun. 30, 2024			36,176	17,348
Ending balance, value at Jun. 30, 2024		1,073,210		$ 17,348	252,917	652,051	0	150,894
Beginning balance, shares at Mar. 31, 2024			36,176	17,348
Beginning balance, value at Mar. 31, 2024		1,067,456		$ 17,348	252,917	646,063	0	151,128
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 23,794	21,754				15,988		5,766
Cash dividends paid to parent by MGE		(10,000)				(10,000)
Distributions to parent from noncontrolling interest		(6,000)						(6,000)
Ending balance, shares at Jun. 30, 2024			36,176	17,348
Ending balance, value at Jun. 30, 2024		$ 1,073,210		$ 17,348	$ 252,917	$ 652,051	$ 0	$ 150,894