Components of Net Periodic Benefit Cost (Detail) - Pension Plans, Defined Benefit - U.S. Pension Plans - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 5.2	$ 4.5	$ 10.5	$ 9.0
Interest cost	4.7	5.2	9.5	10.3
Expected return on plan assets	(4.5)	(3.9)	(8.9)	(7.7)
Amortization of prior service cost	(0.4)	0.1	(0.9)	0.2
Amortization of actuarial loss	1.1	0.6	2.3	1.2
Net Periodic Benefit Cost	$ 6.1	$ 6.5	$ 12.5	$ 13.0