Income Taxes - Provision for Income Taxes (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Currently payable
Federal		$ 3.0	$ 0.0	$ 0.0
International	[1]	101.7	88.5	112.2
Total current taxes		104.7	88.5	112.2
Deferred
International	[1]	(11.4)	(92.5)	(44.8)
Total deferred taxes		(11.4)	(92.5)	(44.8)
Total provision (benefit) for income taxes		$ 93.3	$ (4.0)	$ 67.4

[1] “Federal” represents U.K. taxes. (2) “International” represents non-U.K. taxes.