Income Taxes - Components of Income Tax Provision (Benefit) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current tax expense:
Federal	$ 228.2	$ 79.6	$ 57.6
State and local	9.8	14.3	1.2
Foreign	59.8	106.0	67.3
Total current expense	297.8	199.9	126.1
Deferred tax expense (benefit):
Federal	56.8	130.1	(15.8)
State and local	(21.2)	5.3	3.6
Foreign	(25.9)	(4.8)	(18.3)
Total deferred tax expense (benefit)	9.7	130.6	(30.5)
Total income tax provision	$ 307.5	$ 330.5	$ 95.6