Income Taxes - (Benefit)/Provision for Income Taxes and Income Taxes Paid (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ (96.1)	$ 65.5	$ (46.2)
State	4.6	9.8	24.4
Foreign	(57.5)	237.7	116.6
Current, Total	(149.0)	313.0	94.8
Deferred:
Federal	(24.2)	(90.2)	37.9
State	(11.5)	(4.2)	(8.8)
Foreign	47.7	(444.3)	(15.7)
Deferred, Total	12.0	(538.7)	13.4
(Benefit) provision for income taxes	(137.0)	(225.7)	108.2
Net income taxes paid	$ 147.4	$ 192.5	$ 237.1