Stock-Based Compensation Expense - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Jan. 31, 2013		Jan. 31, 2012		Jan. 31, 2011
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Number of Active Stock Plans	2
Number of Expired Plans	8
Share-Based Compensation Shares Granted to Share Issued	$ 2.11
Shares available for future issuance	50,200,000
Total compensation costs related to non-vested options	$ 34.8
Total compensation costs related to non-vested options, expected to be recognized over a weighted average period (in years)	1 year
Sale of Stock, Price Per Share	$ 38.88
Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount	8.1		0		0
Total compensation cost related to non-vested awards not yet recognized	5.8
Total compensation cost related to non-vested awards not yet recognized, weighted average period of recognition (in years)	1 year 1 month 9 days
Percentage of compensation that eligible employees can use to purchase common stock, maximum	15.00%
Percentage of fair market value eligible employees can purchase common stock, minimum	85.00%
Shares available for future issuance, increases on the first trading day of each fiscal year	10,000,000
Shares available for future issuance, percentage of outstanding shares plus any shares repurchased by Autodesk	2.00%
Weighted average grant date fair value	$ 13.39	[1]	$ 14.04	[1]	$ 9.30	[1]
Restricted Stock Units (RSUs)
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Restricted stock granted	3,400,000		500,000
Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount	70.5		29.1		8.9
Total compensation cost related to non-vested awards not yet recognized			93.0
Total compensation cost related to non-vested awards not yet recognized, weighted average period of recognition (in years)					1 year 9 months 18 days
Restricted Stock Awards
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Number of restricted stock granted but unreleased	4,500,000
Employee Stock Plan 2012
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares of common stock reserved for issuance	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 Maximum Vesting Period For Stock Options	3 years
Shares available for future issuance	11,600,000
Outside directors stock plan 2012
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares of common stock reserved for issuance	2,600,000
Share Based Compensation Arrangement By Share Based Payment Award Maximum Vesting Period For Stock Options	1 year
Shares available for future issuance	2,400,000
ESP Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares available for future issuance	36,200,000
Shares issued under the ESP Plan	2,900,000		2,800,000		3,200,000
Shares issued under the ESP Plan, average price	$ 21.79		$ 18.26		$ 14.77
Weighted average grant date fair value	$ 12.21		$ 9.95		$ 10.11
Employee Service Share Based Compensation recognized Compensation Costs On Nonvested Restricted Shares	34.0		23.8		18.2
Restricted Stock Units (RSUs) | Outside directors stock plan 2012
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	200,000
Stock Options and Restricted Stock [Member] | Employee Stock Plan 2012
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share based compensation arrangement by share based payment award options expiration term	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	7,000,000
Socialcam [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share Based Compensation Cost Incurred Acceleration of Equity Awards	$ 16.6

[1] The weighted average grant date fair value per share of stock options granted is calculated, as of the stock option grant date, using the BSM option pricing model.