STOCKHOLDERS' EQUITY: - Treasury Stock (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Activity in treasury stock
Balance at beginning of period	$ 3,149.0
Balance at end of period	2,700.7	$ 3,149.0
Parent Company (Grupo Mexico) common shares
Activity in treasury stock
Balance at beginning of period	2,766.6	2,766.9
Dividend paid in Common Stock	(428.9)
Used for corporate purposes	$ (0.4)	(0.3)
Balance at end of period		$ 2,766.6	$ 2,766.9
Treasury stock balance at the end of the period (in shares)	94,185,981	111,485,617
Parent Company (Grupo Mexico)
Activity in treasury stock
Balance at beginning of period	$ 382.4	$ 340.7
Other activity, including dividend, interest and foreign currency translation effect	(19.0)	41.7
Balance at end of period	$ 363.4	$ 382.4	340.7
Treasury stock balance at the end of the period (in shares)	61,972,864	67,793,020
TREASURY STOCK:
Activity in treasury stock
Dividend paid in Common Stock	$ (428.9)
TREASURY STOCK: | Parent Company (Grupo Mexico) common shares
Activity in treasury stock
Dividend paid in Common Stock	(428.9)
Used for corporate purposes	(0.4)	$ (0.3)	(0.3)
TREASURY STOCK: | Parent Company (Grupo Mexico)
Activity in treasury stock
Other activity, including dividend, interest and foreign currency translation effect	$ (19.0)	$ 41.7	$ 33.9