Financial Instruments Fair Value of Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Jul. 31, 2014		Jan. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative, notional amount	$ 403.0		$ 351.7
Net gain on derivative instruments	2.0		3.5
Derivative assets	10.0		21.3
Derivative liabilities	1.0		1.7
Not designated as hedging instrument | Prepaid expenses and other current assets and Other assets
Derivatives, Fair Value [Line Items]
Derivative assets	4.1		16.9
Foreign currency contracts
Derivatives, Fair Value [Line Items]
Derivative, notional amount	5.2		205.5
Foreign currency contracts | Designated as hedging instrument | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative assets	5.9	[1]	4.4	[1]
Derivative assets, gross	6.7		5.9
Foreign currency contracts | Designated as hedging instrument | Other accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	1.0	[2]	1.7	[2]
Derivative liabilities, gross	$ 1.9		$ 3.2

[1] Considering Autodesk's master netting arrangements, these contracts are presented net settled. The gross balance is $6.7 million and $5.9 million at July 31, 2014 and January 31, 2014, respectively.

[2] Considering Autodesk's master netting arrangements, these contracts are presented net settled. The gross balance is $1.9 million and $3.2 million at July 31, 2014 and January 31, 2014, respectively.