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							3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended					0 Months Ended			0 Months Ended			0 Months Ended		3 Months Ended		9 Months Ended
	Oct. 31, 2014 StockPlans		Oct. 31, 2013		Oct. 31, 2014 StockPlans		Oct. 31, 2013		Oct. 31, 2014 Restricted Stock Units (RSUs) and Performance Shares	Oct. 31, 2013 Restricted Stock Units (RSUs) and Performance Shares	Jan. 31, 2014 Restricted Stock Units (RSUs) and Performance Shares	Oct. 31, 2014 Restricted Stock Units (RSUs)	Oct. 31, 2013 Restricted Stock Units (RSUs)	Oct. 31, 2014 Restricted Stock Units (RSUs)	Oct. 31, 2013 Restricted Stock Units (RSUs)	Oct. 31, 2014 Performance Stock Unit	Oct. 31, 2013 Performance Stock Unit	Oct. 31, 2014 Performance Stock Unit	Oct. 31, 2013 Performance Stock Unit	Oct. 31, 2014 Performance Stock Unit Share-based compensation award, tranche one	Oct. 31, 2014 Performance Stock Unit Share-based compensation award, tranche two	Oct. 31, 2014 Performance Stock Unit Share-based compensation award, tranche three	Oct. 31, 2014 Employee Stock Plan 2012	Jan. 14, 2014 Employee Stock Plan 2012	Oct. 31, 2014 Employee Stock Plan 2012	Oct. 31, 2014 Employee Stock Plan 2012 Maximum	Oct. 31, 2014 Directors stock plan 2012	Oct. 31, 2014 Directors stock plan 2012	Oct. 31, 2014 Directors stock plan 2012 Minimum	Oct. 31, 2014 Directors stock plan 2012 Maximum	Oct. 31, 2014 ESP Plan	Oct. 31, 2013 ESP Plan	Oct. 31, 2014 ESP Plan	Oct. 31, 2013 ESP Plan
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Share based compensation arrangements by share based payment awards, number of active plans (plan)	2				2
Share based compensation arrangement by share based payment award expired or terminated plans (plan)	7				7
Awards, number of additional shares authorized																								11,400,000
Awards, number of shares authorized																									32,600,000			2,600,000
Stock issued during period, shares, restricted stock award, net of forfeitures																							26,600,000
Stock issued during period, shares, share-based compensation, forfeited																							6,000,000
Share-based compensation shares granted to share issued																							1.79				2.11
Options granted in period					0	[1]																	20,500,000				600,000
Award vesting period																							3 years						1 year	3 years
Share based compensation arrangement by share based payment award options expiration term (in years)																										10 years
Employee stock plan shares remaining available for issuance																									13,900,000			2,000,000			36,000,000		36,000,000
Sale of stock, price per share (in usd per share)	$ 57.54				$ 57.54
Nonvested awards, total compensation cost not yet recognized	$ 1.6				$ 1.6							$ 236.2		$ 236.2		$ 7.0		$ 7.0
Nonvested options outstanding, weighted average remaining contractual term					4 months 9 days
Awards granted in period, weighted average grant date fair value (in usd per share)									$ 52.89	$ 40.64
Awards vested in period, fair value									78.6	49.0
Awards granted in period									3,572,000					3,100,000				500,000
PSU Annual Vesting Percentage																				33.33%	33.33%	33.33%
Allocated share-based compensation expense												$ 31.2	$ 18.8	$ 82.1	$ 52.4	$ 4.9	$ 2.1	$ 12.7	$ 6.9
Nonvested awards, total compensation cost not yet recognized, period for recognition														1 year 10 months 17 days				1 year 0 months 14 days
Awards, nonvested, number									7,569,700		6,515,600	6,700,000		6,700,000		900,000		900,000
Employee stock purchase plan maximum percentage of compensation to purchase shares by eligible participants																																	15.00%
Employee stock purchase plan minimum percentage of common stock fair value defined to purchase shares by eligible participants																																	85.00%
Options, other increases (decreases) in period																																	10,000,000
Options, other increases (decreases) in period percentage calculation																																	2.00%
Shares issued under employee stock purchase plans																															1,000,000	1,400,000	2,100,000	2,900,000
Awards issued, share average price (in usd per share)																															$ 34.19	$ 22.95	$ 33.91	$ 22.61
Weighted average grant date fair value per share of stock options granted (in dollars per share)	$ 0.00	[2]	$ 0.00	[2]	$ 0.00	[2]	$ 0.00	[2]																							$ 15.44	$ 11.80	$ 15.14	$ 11.80

[1] Autodesk did not grant stock options in the nine months ended October 31, 2014.

[2] The weighted average grant date fair value per share of stock options granted is calculated, as of the stock option grant date, using the Black-Scholes Merton ("BSM") option pricing model. For the three and nine months ended October 31, 2014 and 2013, Autodesk did not grant stock options.