Financial Instrument Assets and (Liabilities) Measured at Fair Value on Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Foreign government bonds and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument assets and (liabilities) measured at fair value		$ 3.6
Forward currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument assets and (liabilities) measured at fair value	1.0	(1.1)
Option currency contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument assets and (liabilities) measured at fair value	0.6	4.3
Interest rate swap contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instrument assets and (liabilities) measured at fair value	$ 13.3	$ 12.1