Financial Instruments Fair Value of Derivative Instruments (Details) - USD ($) $ in Millions		Oct. 31, 2015	Jan. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Assets		$ 4.2	$ 21.3
Derivative Liabilities		2.6	5.4
Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative, notional amount		328.3	336.6
Net gain expected to be recognized in next 12 months		20.6
Foreign currency contracts | Designated as hedging instrument | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative Assets	[1]	2.9	20.4
Derivative assets, gross		6.4	23.8
Foreign currency contracts | Designated as hedging instrument | Other accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	[2]	2.0	5.4
Derivative liabilities, gross		5.5	8.7
Foreign currency contracts | Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative, notional amount		1.5	44.6
Foreign currency contracts | Derivatives not designated as hedging instruments | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative Assets		1.3	0.9
Foreign currency contracts | Derivatives not designated as hedging instruments | Other accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities		$ 0.6	$ 0.0

[1] Considering Autodesk's master netting arrangements, these contracts are presented net settled. The gross balance is $6.4 million and $23.8 million at October 31, 2015 and January 31, 2015, respectively.

[2] Considering Autodesk's master netting arrangements, these contracts are presented net settled. The gross balance is $5.5 million and $8.7 million at October 31, 2015 and January 31, 2015, respectively.