Income Taxes - Components of Comprehensive Provision for Income Taxes Allocation (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Schedule Of Income Tax [Line Items]
Expected tax benefit, at U.S. federal statutory income tax rate of 35%	$ (39.3)	$ (2.6)	$ (25.4)	$ (13.3)
Incremental net tax on earnings and losses of non-U.S., U.S. and non-tax group companies	37.1	0.3	48.3	2.7
Non-U.S. tax rates	(2.3)	(0.6)	(4.7)	(0.4)
Valuation allowance	(157.6)	2.9	(162.6)	2.9
Adjustment to the reserve for uncertain tax positions, net	0.6	0.4	1.1	0.6
Nondeductible expenses	0.3	0.5	0.8	0.6
Domestic production activities deduction	(1.5)	(0.5)	(2.1)	(0.8)
U.S. state income taxes	(4.7)	(0.1)	(4.7)	(0.5)
Other, net		(0.1)	(0.1)	(0.2)
Income tax expense (benefit)	(167.4)	0.2	(149.4)	(8.4)
Comprehensive provision for income taxes (benefit) allocable to:
Income tax expense (benefit)	(167.4)	0.2	(149.4)	(8.4)
Other comprehensive income (loss):
Marketable securities	(0.3)	0.4	(0.5)	0.2
Currency translation	16.4	(1.0)	18.1	1.8
Interest rate swap	(0.3)	(0.6)	0.1	(2.7)
Total	(149.5)	(0.3)	(128.8)	(7.8)
Pension Plans
Other comprehensive income (loss):
Defined benefit plans	2.2	0.9	3.1	1.7
OPEB Plans
Other comprehensive income (loss):
Defined benefit plans	$ (0.1)	$ (0.2)	$ (0.2)	$ (0.4)