Stock-based Compensation Expense Schedule Of Share-based Compensation Options Activity (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended
	Oct. 31, 2014		Jan. 31, 2014
Number of Shares
Options outstanding (in shares)	5.9
Granted (in shares)	0	[1]
Exercised (in shares)	(2.7)
Canceled/Forfeited (in shares)	0
Options outstanding (in shares)	3.2
Options vested and exercisable (in shares)	2.9
Options vested (in shares)	3.2	[2]
Options available (in shares)	15.9
Weighted average exercise price per share
Outstanding (in dollars per share)	$ 34.12		$ 33.54
Granted (in dollars per share)	$ 0.00	[1]
Exercised (in dollars per share)	$ 32.87
Canceled/Forfeited (in dollars per share)	$ 0.00
Vested and exercisable (in dollars per share)	$ 33.44
Vested (in dollars per share)	$ 34.12	[2]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding, Weighted average remaining contractual term	4 years 3 months 3 days
Options vested and exercisable, Weighted average remaining contractual term	4 years 0 months 10 days
Options vested, Weighted average remaining contractual term	4 years 3 months 3 days	[2]
Options outstanding, Aggregate Intrinsic Value	$ 74.6	[3]
Options vested and exercisable, Aggregate Intrinsic Value	69.4	[3]
Options vested, Aggregate Intrinsic Value	$ 74.6	[2],[3]
$2.28 - $29.49
Number of Shares
Options outstanding (in shares)	1.1
Options vested and exercisable (in shares)	1.1
Weighted average exercise price per share
Outstanding (in dollars per share)	$ 23.80
Vested and exercisable (in dollars per share)	$ 23.74
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise Price, Lower Limit (in dollars per share)	$ 2.28
Exercise Price, Upper Limit (in dollars per share)	$ 29.49
$29.50 - $41.62
Number of Shares
Options outstanding (in shares)	1.6
Options vested and exercisable (in shares)	1.4
Weighted average exercise price per share
Outstanding (in dollars per share)	$ 38.41
Vested and exercisable (in dollars per share)	$ 38.39
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise Price, Lower Limit (in dollars per share)	$ 29.5
Exercise Price, Upper Limit (in dollars per share)	$ 41.62
$42.39 - $43.81
Number of Shares
Options outstanding (in shares)	0.5
Options vested and exercisable (in shares)	0.4
Weighted average exercise price per share
Outstanding (in dollars per share)	$ 43.79
Vested and exercisable (in dollars per share)	$ 43.80
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise Price, Lower Limit (in dollars per share)	$ 42.39
Exercise Price, Upper Limit (in dollars per share)	$ 43.81

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

[2] Options expected to vest reflect an estimated forfeiture rate.

[3] Represents the total pre-tax intrinsic value, based on Autodesk’s closing stock price of $57.54 per share as of October 31, 2014, which would have been received by the option holders had all option holders exercised their options as of that date.