Net (Loss) Income Per Share - Computation of Net Income Per Share Amounts (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended										12 Months Ended
	Jan. 31, 2016	[1]	Oct. 31, 2015	Jul. 31, 2015	[2]	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2016		Jan. 31, 2015	Jan. 31, 2014
Numerator:
Net (loss) income	$ (37.2)		$ (43.8)	$ (268.6)		$ 19.1	$ 11.5	$ 10.7	$ 31.3	$ 28.3	$ (330.5)		$ 81.8	$ 228.8
Denominator:
Denominator for basic net (loss) income per share—weighted average shares											226.0		227.1	224.0
Effect of dilutive securities (1)											0.0	[3]	5.3	5.6
Denominator for dilutive net (loss) income per share											226.0		232.4	229.6
Basic net (loss) income per share (usd per share)	$ (0.17)		$ (0.19)	$ (1.18)		$ 0.08	$ 0.05	$ 0.05	$ 0.14	$ 0.12	$ (1.46)		$ 0.36	$ 1.02
Diluted net (loss) income per share (usd per share)	$ (0.17)		$ (0.19)	$ (1.18)		$ 0.08	$ 0.05	$ 0.05	$ 0.13	$ 0.12	$ (1.46)		$ 0.35	$ 1.00

[1] Subsequent to furnishing preliminary financial statements on Form 8-K on February 25, 2016 for the three and twelve months ended January 31, 2016, Autodesk identified a $4.5 million tax adjustment associated with deemed foreign withholding taxes related to non-permanently reinvested earnings in foreign jurisdictions which have not yet repatriated resulting in changes to the Consolidated Financial Statements as reflected in this Annual Report on Form 10-K. This non-cash adjustment resulted in an increase to GAAP diluted loss per share from $(0.15) to $(0.17) for the three months ended January 31, 2016.

[2] Certain second quarter fiscal 2016 balances have been revised to include the correction of an error identified in the third quarter of fiscal 2016, resulting in an additional $33.1 million of income tax expense from the previously reported results, primarily related to the establishment of a valuation allowance. See Note 1, "Business and Summary of Significant Accounting Policies" for further discussion.

[3] (1)Dilutive securities of 4.7 million shares for the fiscal year ended January 31, 2016 have been excluded from the calculation of diluted net (loss) income per share as those shares would have been anti-dilutive due to the net loss incurred during this period