Employee Benefits - Net Periodic Pension Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted-Average Assumptions:
Expected Long-Term Rate of Return on Assets	5.25%
Supplemental Plan
Defined Benefit plan Net periodic benefit cost
Service Cost	$ 4.1	$ 4.3	$ 3.7
Interest Cost	5.8	5.3	5.2
Settlement Expense	0.0	0.0	0.0
Amortization:
Net Actuarial Loss	5.6	7.4	5.7
Prior Service (Benefit) Cost	0.2	0.2	0.2
Net Periodic Pension Expense	$ 15.7	$ 17.2	$ 14.8
Weighted-Average Assumptions:
Discount Rates	4.47%	3.79%	4.46%
Rate of Increase in Compensation Level	4.39%	4.39%	4.39%
U.S. Plan | Pension Plans, Defined Benefit
Defined Benefit plan Net periodic benefit cost
Service Cost	$ 41.6	$ 41.4	$ 38.3
Interest Cost	47.2	44.3	45.9
Expected Return on Plan Assets	(86.9)	(88.2)	(93.8)
Settlement Expense	0.0	0.0	0.0
Amortization:
Net Actuarial Loss	17.2	28.2	19.0
Prior Service (Benefit) Cost	(0.4)	(0.4)	(0.4)
Net Periodic Pension Expense	$ 18.7	$ 25.3	$ 9.0
Weighted-Average Assumptions:
Discount Rates	4.47%	3.79%	4.46%
Rate of Increase in Compensation Level	4.39%	4.39%	4.39%
Expected Long-Term Rate of Return on Assets	6.00%	6.00%	6.75%
Non U.S. Plans | Pension Plans, Defined Benefit
Defined Benefit plan Net periodic benefit cost
Service Cost	$ 2.0	$ 1.7	$ 0.4
Interest Cost	3.9	4.0	4.0
Expected Return on Plan Assets	(4.4)	(4.4)	(4.5)
Settlement Expense	0.0	0.5	1.1
Amortization:
Net Actuarial Loss	0.6	0.9	1.3
Prior Service (Benefit) Cost	0.3	0.2	0.1
Net Periodic Pension Expense	$ 2.4	$ 2.9	$ 2.4
Weighted-Average Assumptions:
Discount Rates	2.16%	2.08%	2.33%
Rate of Increase in Compensation Level	1.75%	1.75%	1.75%
Expected Long-Term Rate of Return on Assets	2.39%	2.61%	3.13%