Financial Instruments Fair Value of Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Oct. 31, 2014		Jan. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative, notional amount	$ 401.0		$ 351.7
Net gain on derivative instruments	23.1		3.5
Derivative Assets	23.4		21.3
Derivative Liabilities	3.0		1.7
Not designated as hedging instrument | Prepaid expenses and other current assets and Other assets
Derivatives, Fair Value [Line Items]
Derivative Assets	3.7		16.9
Foreign currency contracts
Derivatives, Fair Value [Line Items]
Derivative, notional amount	24.5		205.5
Foreign currency contracts | Designated as hedging instrument | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative Assets	19.7	[1]	4.4	[1]
Derivative assets, gross	20.3		5.9
Foreign currency contracts | Designated as hedging instrument | Other accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative Liabilities	3.0	[2]	1.7	[2]
Derivative liabilities, gross	$ 3.6		$ 3.2

[1] Considering Autodesk's master netting arrangements, these contracts are presented net settled. The gross balance is $20.3 million and $5.9 million at October 31, 2014 and January 31, 2014, respectively.

[2] Considering Autodesk's master netting arrangements, these contracts are presented net settled. The gross balance is $3.6 million and $3.2 million at October 31, 2014 and January 31, 2014, respectively.