Derivatives Not Designated As Hedging Instruments (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Other Financial Items, net
Interest Expense	0	0	0	0
Interest Income
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Nominal Volume	1,449.0	1,212.6	1,449.0	1,212.6
Interest Income
Not Designated as Hedging Instrument | Foreign Exchange Contract
Derivative Instruments, Gain (Loss) [Line Items]
Nominal Volume	1,449.0	1,172.3	1,449.0	1,172.3
Other Financial Items, net	(4.4)	(13.0)	(9.9)	(13.0)
Interest Expense	(0.1)	0.7	0.1	0.7
Interest Income
Not Designated as Hedging Instrument | Cross Currency Interest Rate Contract | Less Than 1 Year
Derivative Instruments, Gain (Loss) [Line Items]
Nominal Volume		40.3		40.3
Other Financial Items, net		0.2		3.5
Interest Expense		0.1		0.1
Interest Income