Income Taxes - Income Tax Data from Continuing Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2015
Income (loss) components:
United States		$ 89.2			$ 87.5			$ 159.3
International		220.2			170.9			223.0
Income from continuing operations before income tax		309.4			258.4			382.3
Current income tax expense (benefit):
United States - federal		7.7			4.3			(8.5)
United States - state and local		1.3			(0.3)			0.1
International		38.6			51.1			52.9
Total current income tax expense (benefit)		47.6			55.1			44.5
Deferred income tax expense (benefit) components:
United States - federal		105.9			26.4			31.9
United States - state and local		4.4			(2.1)			6.0
International		36.7			(3.4)			(12.3)
Total deferred income tax expense (benefit)		147.0			20.9			25.6
Income tax expense (benefit)		$ 194.6			$ 76.0			$ 70.1
Effective income tax rate	62.90%		62.90%	29.40%		29.40%	18.30%		18.30%