Financial Instruments Effects of Derivative Instruments on Condensed Consolidated Statements of Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012	Oct. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Net Income (Loss) Attributable to Parent	$ 29.4	$ 72.8	$ 172.9	$ 213.3
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in accumulated other comprehensive income on derivatives (effective portion)	(9.4)	(1.0)	2.7	(3.6)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	2.5	2.3	11.0	(0.9)
Sales [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	3.2	0.8	15.6	(6.8)
Operating Expense [Member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(0.7)	1.5	(4.6)	5.9
Interest and other income (expense), net [member] | Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest and other income (expense), net	(0.1)	0.1	0	0.1
Interest and other income (expense), net [member] | Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest and other income, net	$ 1.6	$ (2.6)	$ 2.6	$ (0.6)