Employee Benefits - Change in Projected Benefit Obligation (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Actuarial Loss (Gain)	$ 256.2	$ (131.4)
Supplemental Plan
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning Balance	135.6	144.5
Service Cost	4.1	4.3	$ 3.7
Interest Cost	5.8	5.3	5.2
Employee Contributions	0.0	0.0
Plan Amendment	0.0	0.0
Actuarial Loss (Gain)	22.0	(9.7)
Settlement	0.0	0.0
Benefits Paid	(18.3)	(8.8)
Foreign Exchange Rate Changes	0.0	0.0
Ending Balance	149.2	135.6	144.5
U.S. Plan | Pension Plans, Defined Benefit
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning Balance	1,092.0	1,209.9
Service Cost	41.6	41.4	38.3
Interest Cost	47.2	44.3	45.9
Employee Contributions	0.0	0.0
Plan Amendment	0.0	0.0
Actuarial Loss (Gain)	213.3	(112.4)
Settlement	0.0	0.0
Benefits Paid	(70.7)	(91.2)
Foreign Exchange Rate Changes	0.0	0.0
Ending Balance	1,323.4	1,092.0	1,209.9
Non U.S. Plans | Pension Plans, Defined Benefit
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning Balance	183.5	198.3
Service Cost	2.0	1.7	0.4
Interest Cost	3.9	4.0	4.0
Employee Contributions	0.6	0.4
Plan Amendment	(0.4)	1.3
Actuarial Loss (Gain)	20.9	(9.3)
Settlement	0.0	(2.7)
Benefits Paid	(3.6)	(1.1)
Foreign Exchange Rate Changes	4.2	(9.1)
Ending Balance	$ 211.1	$ 183.5	$ 198.3