Income Taxes - Component of Income Taxes Expenses (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014	Mar. 31, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Tax Expenses [Line Items]
Expected tax expense (benefit), at U.S. federal statutory income tax rate of 35%	$ 18.6		$ (21.0)	$ 30.4	$ (72.0)
Incremental tax (benefit) on earnings of non-U.S. and non-tax group companies	(1.4)		1.3	(2.6)	(3.4)
Non-U.S. tax rates	(1.3)		0.8	(3.0)	3.3
Adjustment to the reserve for uncertain tax positions, net	0.5		0.6	(5.1)	2.3
Nondeductible expenses	0.9		0.5	2.1	3.1
Adjustment to prior year taxes	(2.0)	1.0		(1.8)
U.S. state income taxes and other, net	0.5		(1.1)	1.1	(1.3)
Income tax expense (benefit)	15.8		(18.9)	21.1	(68.0)
Comprehensive provision for income taxes (benefit) allocable to:
Net income (loss)	15.8		(18.9)	21.1	(68.0)
Other comprehensive income (loss):
Marketable securities	0.1		6.3	(11.1)	7.5
Currency translation	(8.9)		4.1	(10.5)	2.8
Total	7.8		(7.5)	1.8	(54.6)
Defined Benefit Pension Plans
Other comprehensive income (loss):
Defined benefit plans	1.0		1.2	2.9	3.6
OPEB
Other comprehensive income (loss):
Defined benefit plans	$ (0.2)		$ (0.2)	$ (0.6)	$ (0.5)