Financial Instruments Effects of Derivative Instruments on Condensed Consolidated Statements of Operations (Details) - Foreign currency contracts - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014
Designated as hedging instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (loss) gain recognized in accumulated other comprehensive income on derivatives (effective portion)	$ (5.0)	$ 22.3	$ 1.7	$ 22.5
Amount and location of gain (loss) reclassified from accumulated other comprehensive income into income (effective portion)	7.1	1.3	23.9	2.9
Designated as hedging instrument | Net revenue
Derivative Instruments, Gain (Loss) [Line Items]
Amount and location of gain (loss) reclassified from accumulated other comprehensive income into income (effective portion)	9.5	2.1	31.8	4.6
Designated as hedging instrument | Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
Amount and location of gain (loss) reclassified from accumulated other comprehensive income into income (effective portion)	(2.4)	(0.8)	(7.9)	(1.7)
Designated as hedging instrument | Interest and other expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Amount and location of (loss) gain recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing)	(0.2)	0.1	(0.5)	0.3
Derivatives not designated as hedging instruments | Interest and other expense, net
Derivative Instruments, Gain (Loss) [Line Items]
Amount and location of loss recognized in income on derivatives (1)	$ (2.5)	$ (4.5)	$ (1.8)	$ (15.1)	[1]

[1] Prior period balances have been adjusted to conform to current period presentation.