Retirement Benefit Plans - Components of Net Pension Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S. and Puerto Rico [Member]
Net Periodic Benefit Cost
Service cost	$ 0.7	$ 7.1	$ 8.0
Interest cost	13.9	16.2	14.2
Expected return on plan assets	(32.9)	(32.4)	(32.9)
Curtailment gain		(7.2)
Settlements	0.5	0.8	1.2
Amortization of prior service cost	0.3	(3.4)	(5.7)
Amortization of unrecognized actuarial loss	7.2	19.3	23.7
Net periodic benefit (income) expense	(10.3)	0.4	8.5
Foreign [Member]
Net Periodic Benefit Cost
Service cost	24.7	19.0	20.0
Interest cost	5.4	9.0	8.1
Expected return on plan assets	(13.3)	(13.4)	(14.0)
Settlements	(0.5)		0.2
Amortization of prior service cost	(4.2)	(3.9)	(4.2)
Amortization of unrecognized actuarial loss	1.3	2.5	2.5
Net periodic benefit (income) expense	$ 13.4	$ 13.2	$ 12.6