Employee and Director Stock Plans Employee and Director stock Options Outstanding (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	Jan. 31, 2012		Jan. 31, 2011
Weighted Average Exercise Price	$ 31.39		$ 28.93
Equity Compensation Plans Approved by Security Holders
Number of securities to be issued upon exercise of outstanding options	30.2
Weighted Average Exercise Price	$ 29.38
Shares available for future issuance	47.7	[1]
Equity Compensation Plans Not Approved by Security Holders
Number of securities to be issued upon exercise of outstanding options	0.4	[2]
Weighted Average Exercise Price	$ 11.03	[2]
Shares available for future issuance	0
Equity Compensation Plans
Number of securities to be issued upon exercise of outstanding options	30.6
Weighted Average Exercise Price	$ 29.15
Shares available for future issuance	47.7

[1] Included in this amount are 29.7 million securities available for future issuance under Autodesk’s ESP Plan.

[2] Amounts correspond to Autodesk’s Nonstatutory Stock Option Plan, which was terminated by the Board of Directors in December 2004.