Income Taxes - Provision for Income Taxes (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Currently payable
Federal	[1]	$ 0.0	$ 0.1	$ 0.0
International	[2]	79.8	70.3	64.2
Total current taxes		79.8	70.4	64.2
Deferred
International	[2]	(9.0)	4.6	(18.4)
Total deferred taxes		(9.0)	4.6	(18.4)
Total provision (benefit) for income taxes		$ 70.8	$ 75.0	$ 45.8

[1] “Federal” represents U.K. taxes.

[2] “International” represents non-U.K. taxes.