Postretirement Benefit Plans - Changes in Projected Benefit Obligations of Pension and Other Employee-Related Defined Benefit Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in benefit obligation
Benefit obligation – January 1	$ 557.1	$ 531.0
Service cost	2.6	3.7
Interest cost	16.0	16.5
Amendments	(0.1)	2.0
Actuarial (gain) loss	(33.8)	20.7
Benefits paid	(31.7)	(30.5)
Acquired	0.0	3.5
Settlement	(6.3)	(0.4)
Foreign currency translation	(4.0)	10.6
Benefit obligation – December 31	499.8	557.1	$ 531.0
Other Postretirement Benefits Plan [Member]
Change in benefit obligation
Benefit obligation – January 1	138.1	138.8
Service cost	0.9	0.8	0.9
Interest cost	4.5	4.4	4.9
Amendments	0.0	0.4
Actuarial (gain) loss	(15.8)	1.9
Benefits paid	(9.1)	(8.2)
Acquired	0.0	0.0
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
Benefit obligation – December 31	118.6	138.1	138.8
Pension Plan [Member]
Change in benefit obligation
Benefit obligation – January 1	419.0
Service cost	1.7	2.9	2.9
Interest cost	11.5	12.1	13.4
Settlement			(1.4)
Benefit obligation – December 31	381.2	419.0
U.S. Plan [Member]
Change in benefit obligation
Settlement			(26.6)
U.S. Plan [Member] | Pension Plan [Member]
Change in benefit obligation
Benefit obligation – January 1	325.7	312.3
Service cost	0.4	1.5	1.6
Interest cost	10.1	10.5	11.9
Amendments	0.0	1.6
Actuarial (gain) loss	(18.9)	19.1
Benefits paid	(19.6)	(19.3)
Acquired	0.0	0.0
Settlement	(5.9)	0.0
Foreign currency translation	0.0	0.0
Benefit obligation – December 31	291.8	325.7	312.3
International Plan [Member] | Pension Plan [Member]
Change in benefit obligation
Benefit obligation – January 1	93.3	79.9
Service cost	1.3	1.4	1.3
Interest cost	1.4	1.6	1.5
Amendments	(0.1)	0.0
Actuarial (gain) loss	0.9	(0.3)
Benefits paid	(3.0)	(3.0)
Acquired	0.0	3.5
Settlement	(0.4)	(0.4)
Foreign currency translation	(4.0)	10.6
Benefit obligation – December 31	$ 89.4	$ 93.3	$ 79.9