Employee Benefit Plans - Components of Net Periodic Defined Benefit Pension Benefit Cost (Credit) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 11.4	$ 9.9
Total	29.9	22.9
Defined Benefit Pension Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Interest cost	2.5	2.7	$ 2.7
Expected return on plan assets	(3.3)	(3.4)	(3.9)
Amortization of unrecognized net actuarial loss	2.0	1.9	1.7
Total	1.2	1.2	0.5
Defined Benefit Pension Plans | Foreign
Defined Benefit Plan Disclosure [Line Items]
Service cost	11.4	9.9	11.2
Interest cost	13.4	15.1	15.1
Settlement loss	0.1
Expected return on plan assets	(9.7)	(14.9)	(17.3)
Amortization of unrecognized prior service credit	0.3	0.2	0.4
Amortization of unrecognized net actuarial loss	13.2	11.4	13.8
Total	28.7	21.7	23.2
OPEB
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.1	0.1	0.1
Interest cost	0.4	0.5	0.5
Amortization of unrecognized prior service credit	(1.1)	(1.8)	(1.9)
Amortization of unrecognized net actuarial loss	(0.2)	(0.1)
Total	$ (0.8)	$ (1.3)	$ (1.3)