Stock-based Compensation Expense Summary of Restricted Stock Award and Restricted Stock Unit Activity (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Oct. 31, 2013		Oct. 31, 2012		Oct. 31, 2013		Oct. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$ 37.4	[1]	$ 7.6	[1]	$ 80.2	[1]	$ 73.5	[1]
PerformanceSharesUnitsPayoutPercentage	92.30%				92.30%
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Awarded					2,800,000
Unreleased restricted stocck at April 30, 2012	5,700,000				5,700,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Awarded					500,000
Forfeited					(14,000)	[2]
Unreleased restricted stocck at April 30, 2012	800,000				800,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Forfeited (in usd per share)					$ 35.94	[2]
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unreleased restricted stock at January 31, 2012					5,020,800
Awarded					3,309,400
Released					(1,434,600)
Forfeited					(341,800)
Unreleased restricted stocck at April 30, 2012	6,539,800				6,539,800
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Unreleased restricted stock at January 31, 2012 (in usd per share)					$ 33.89
Awarded (in usd per share)					$ 40.64
Released (in usd per share)					$ 34.16
Forfeited (in usd per share)					$ 35.17
Unreleased restricted stock at April 30, 2012 (in usd per share)	$ 37.39				$ 37.39

[1] The intrinsic value of options exercised is calculated as the difference between the exercise price of the option and the market value of the stock on the date of exercise.

[2] Based on Autodesk's financial results for the performance period, the fiscal 2013 performance stock units were earned at 92.3% of the target award. The vesting of the performance stock units is subject to the holders satisfying the remaining service condition of the awards.