Gains and Losses Recorded in Consolidated Statement of Income related to Derivative Instruments Not Formally Designated as Hedges (Detail) (Nondesignated, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Income	$ (1.4)	$ (5.0)
Credit Default Swap Contracts | Others Operating Income
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Income	(1.1)	0.5
Forward Contracts | Others Operating Income
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Income		0.1
Foreign Exchange Contracts | Others Operating Income
Derivative Instruments, Gain (Loss) [Line Items]
Amount Recognized in Income	$ (0.3)	$ (5.6)