Component of Income Tax Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Line Items]
Current income taxes, U.S.	$ 2.3	$ (0.6)	$ 5.7
Current income taxes, Non-U.S.	16.1
Current income taxes, Subtotal	18.4	(0.6)	5.7
Deferred income taxes, U.S.	(42.7)	(20.3)	50.3
Deferred income taxes, Non-U.S.	6.9	11.0
Deferred income taxes, Subtotal	(35.8)	(9.3)	50.3
Total income tax expense (benefit)	$ (17.4)	$ (9.9)	$ 56.0