Employee Benefit Plans - Employee Savings Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Maximum percentage of pre-tax compensation an employee can contribute to savings plan	50.00%
Percentage of matching contribution on employee savings plan	100.00%
Trust assets	$ 51.0	$ 56.4
Employee savings plan expense	646.2	562.9	$ 522.7
Employee Savings Plan [Member] | Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Trust assets	17.9
Related benefit obligation	44.2
Employee savings plan expense	$ 32.3	$ 29.1	$ 25.4
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Maximum percentage employer will match on pre-tax compensation	4.00%