Stock-based Compensation Expense Stock-Based Compensation Expense - Additional Information (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
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share based compensation arragements by share based payment awards, number of active plans (presented as an integer)	2		2
Share based compensation arrangement by share based payment award expired or terminated plans (presented as an integer)	8		8
Share-Based Compensation Shares Granted to Share Issued			$ 2.11
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures			0	[1]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized (in usd)	$ 14.5		$ 14.5
Share Based Compensation Non Vested Options Outstanding Weighted Average Remaining Contractual Term (in years)	8 months 15 days		8 months 15 days
Sale of Stock, Price Per Share (in usd per share)	$ 39.90		$ 39.90
Employee Service Share Based Compensation Unrecognized Compensation Costs On Nonvested Restricted Shares (in usd)	14.5		14.5
Proposed share increase to amended 2012 plan	11,400,000		11,400,000
Employee Stock Plan 2012 [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	21,200,000		21,200,000
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures			15,200,000
Stock Issued During Period, Shares, Share-based Compensation, Forfeited			6,000,000
Share-Based Compensation Shares Granted to Share Issued			$ 1.79
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures			12,700,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (in years)			3 years
Employee Stock Plan Shares Remaining Available For Issuance	9,300,000		9,300,000
Employee Stock Plan 2012 [Member] | Maximum [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share based compensation arrangement by share based payment award options expiration term (in years)			10 years
Directors stock plan 2012 [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	2,600,000		2,600,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures			400,000
Employee Stock Plan Shares Remaining Available For Issuance	2,200,000		2,200,000
Directors stock plan 2012 [Member] | Maximum [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (in years)	3 years
Directors stock plan 2012 [Member] | Minimum [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (in years)	1 year
Employee Qualified Stock Purchase Plan 1998 ESP Plan [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Employee Stock Plan Shares Remaining Available For Issuance	33,300,000		33,300,000
Employee Stock Purchase Plan Maximum Percentage Of Compensation To Purchase Shares By Eligible Participants (presented as a percent)			15.00%
Employee Stock Purchase Plan Minimum Percentage Of Common Stock Fair Value Defined To Purchase Shares By Eligible Participants (presented as a percent)			85.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Other Increases (Decreases) in Period			10,000,000
Share Based Compensation Arrangement By Share Based Payment Award Options Other Increases Decreases In Period Percentage Calculation (presented as a percent)			2.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans	1,400,000	1,300,000	2,900,000		2,900,000
Share Based Compensation Arrangement By Share Based Payment Award Shares Issued Average Price (in usd per share)	$ 22.95	$ 21.98	$ 22.61		$ 21.79
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in usd per share)		$ 11.57	$ 11.80		$ 11.02
Restricted Stock Units (RSUs) [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition (in years)			1 year 10 months 13 days
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized (in usd)	141.9		141.9
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			2,800,000
Allocated Share-based Compensation Expense (in usd)	18.8	31.8	52.4		55.1
Employee Service Share Based Compensation Unrecognized Compensation Costs On Nonvested Restricted Shares (in usd)	141.9		141.9
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	5,700,000		5,700,000
Performance Shares [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition (in years)			1 year 1 month 27 days
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized (in usd)	4.6		4.6
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			500,000
Allocated Share-based Compensation Expense (in usd)	2.1	1.9	6.9		5.2
Employee Service Share Based Compensation Unrecognized Compensation Costs On Nonvested Restricted Shares (in usd)	$ 4.6		$ 4.6
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	800,000		800,000

[1] Autodesk did not grant stock options in the nine months ended October 31, 2013.