Financial Instruments Fair Value of Derivative Instruments (Details) (USD $) In Millions, unless otherwise specified	Oct. 31, 2013		Jan. 31, 2013
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	$ 9.9	[1]	$ 13.5	[1]
Derivative Asset, Fair Value, Gross Asset	12.1		17.4
Not Designated as Hedging Instrument [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	9.8		10.7
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Prepaid expenses and other current assets [member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	2.3	[2]	6.7	[2]
Derivative Asset, Fair Value, Gross Asset	4.0		8.2
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member] | Other Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	2.2	[3]	3.9	[3]
Derivative Liability, Fair Value, Gross Liability	$ 3.9		$ 5.4

[1] Included in “Prepaid expenses and other current assets,” “Other assets,” or “Other accrued liabilities” in the accompanying Condensed Consolidated Balance Sheets.

[2] Considering Autodesk's master netting arrangements, these contracts are presented net settled. The gross balance is $4.0 million and $8.2 million at October 31, 2013 and January 31, 2013, respectively.

[3] Considering Autodesk's master netting arrangements, these contracts are presented net settled. The gross balance is $3.9 million and $5.4 million at October 31, 2013 and January 31, 2013, respectively.