Employee Benefits - Employee Benefit Plan Status (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Plan Assets at Fair Value	$ 1,793.7	$ 1,601.2
Supplemental Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	139.8	131.5
Projected Benefit Obligation	162.3	149.2	$ 135.6
Plan Assets at Fair Value	0.0	0.0
Funded Status at end of year	$ (162.3)	$ (149.2)
Weighted-Average Assumptions:
Discount Rates	2.45%	3.37%
Rate of Increase in Compensation Level	4.97%	4.97%
U.S. Plan | Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	$ 1,312.9	$ 1,181.9
Projected Benefit Obligation	1,470.6	1,323.4	1,092.0
Plan Assets at Fair Value	1,793.7	1,601.2	1,380.1
Funded Status at end of year	$ 323.1	$ 277.8
Weighted-Average Assumptions:
Discount Rates	2.75%	3.37%
Rate of Increase in Compensation Level	4.97%	4.97%
Expected Long-Term Rate of Return on Assets	5.25%	5.25%
Non U.S. Plans | Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	$ 228.5	$ 204.7
Projected Benefit Obligation	236.1	211.1	183.5
Plan Assets at Fair Value	211.5	190.1	$ 166.7
Funded Status at end of year	$ (24.6)	$ (21.0)
Weighted-Average Assumptions:
Discount Rates	0.93%	1.40%
Rate of Increase in Compensation Level	1.50%	1.50%
Expected Long-Term Rate of Return on Assets	1.28%	1.72%