Income Taxes - Income Tax Data from Continuing Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016
Income (loss) components:
United States	$ 114.4			$ 89.2			$ 87.5
International	276.6			220.2			170.9
Income from continuing operations before income tax	391.0			309.4			258.4
Current income tax expense (benefit):
United States - federal	6.3			7.7			4.3
United States - state and local	7.9			1.3			(0.3)
International	58.2			38.6			51.1
Total current income tax expense (benefit)	72.4			47.6			55.1
Deferred income tax expense (benefit) components:
United States - federal	7.4			105.9			26.4
United States - state and local	(0.2)			4.4			(2.1)
International	(21.9)			36.7			(3.4)
Total deferred income tax expense (benefit)	(14.7)			147.0			20.9
Income tax expense (benefit)	$ 57.7			$ 194.6			$ 76.0
Effective income tax rate		14.80%	14.80%		62.90%	62.90%		29.40%	29.40%