Stock-based Compensation Expense Schedule Of Share-based Compensation Options Activity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		6 Months Ended
		Jul. 31, 2015	Jan. 31, 2015
Number of Shares
Options outstanding (in shares)		2.7
Granted (in shares)	[1]	0.0
Exercised (in shares)		(0.6)
Canceled/Forfeited (in shares)		0.0
Options outstanding (in shares)		2.1
Options vested and exercisable (in shares)		2.1
Options available (in shares)		24.4
Weighted average exercise price per share
Outstanding (in dollars per share)		$ 35.07	$ 34.46
Granted (in dollars per share)	[1]	0.00
Exercised (in dollars per share)		32.53
Canceled/Forfeited (in dollars per share)		0.00
Vested and exercisable (in dollars per share)		$ 35.10
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding, Weighted average remaining contractual term		3 years 11 months 1 day
Options vested and exercisable, Weighted average remaining contractual term		3 years 10 months 27 days
Options outstanding, Aggregate Intrinsic Value	[2]	$ 32.1
Options vested and exercisable, Aggregate Intrinsic Value	[2]	$ 32.0
Sale of stock, price per share (in usd per share)		$ 50.58
$12.31 - $29.49
Number of Shares
Options outstanding (in shares)		0.7
Options vested and exercisable (in shares)		0.7
Weighted average exercise price per share
Outstanding (in dollars per share)		$ 24.10
Vested and exercisable (in dollars per share)		24.05
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise Price, Lower Limit (in dollars per share)		12.31
Exercise Price, Upper Limit (in dollars per share)		$ 29.49
$29.50 - $41.62
Number of Shares
Options outstanding (in shares)		0.9
Options vested and exercisable (in shares)		0.9
Weighted average exercise price per share
Outstanding (in dollars per share)		$ 39.67
Vested and exercisable (in dollars per share)		39.68
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercise Price, Lower Limit (in dollars per share)		29.50
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)		0.5
Weighted average exercise price per share
Outstanding (in dollars per share)		$ 43.80
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 six months ended July 31, 2015.

[2] Represents the total pre-tax intrinsic value, based on Autodesk’s closing stock price of $50.58 per share as of July 31, 2015, which would have been received by the option holders had all option holders exercised their options as of that date.