Financial Instruments Fair Value of Derivative Instruments (Details) - USD ($) $ in Millions	Apr. 30, 2016	Jan. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 5.7	$ 8.3
Derivative Liabilities	9.3	6.4
Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative, notional amount	313.8	142.4
Net gain expected to be recognized in next 12 months	6.2
Foreign currency contracts | Designated as hedging instrument | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative Assets	5.0	3.4
Foreign currency contracts | Designated as hedging instrument | Other accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	6.5	3.4
Foreign currency contracts | Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative, notional amount	40.2	231.6
Foreign currency contracts | Derivatives not designated as hedging instruments | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative Assets	0.7	4.9
Foreign currency contracts | Derivatives not designated as hedging instruments | Other accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 2.8	$ 3.0