Other Comprehensive Loss - Schedule of Components of Other Comprehensive Loss and Income Tax Expense Allocated to Each Component (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive loss, Before Tax Amount	$ (31.8)	$ (24.6)	$ (42.8)
Other comprehensive loss, Income Tax	(9.3)	3.9	4.5
Other comprehensive loss	(22.5)	(28.5)	(47.3)
Translation adjustments
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive loss, Before Tax Amount	7.0	(39.9)	57.1
Other comprehensive loss	7.0	(39.9)	57.1
Adjustment for net periodic pension and OPEB plan cost
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive loss, Before Tax Amount	(39.8)	15.3	22.4
Other comprehensive loss, Income Tax	(9.3)	3.9	7.5
Other comprehensive loss	(30.5)	$ 11.4	14.9
Adjustment for available-for-sale securities
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive loss, Before Tax Amount			(122.3)
Other comprehensive loss, Income Tax			(3.0)
Other comprehensive loss			$ (119.3)
Changes in Fair Value of Derivatives
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive loss, Before Tax Amount	1.0
Other comprehensive loss	$ 1.0