Business and Summary of Significant Accounting Policies - Reclassifications (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended										6 Months Ended	12 Months Ended
	Jan. 31, 2016		Oct. 31, 2015	Jul. 31, 2015		Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jul. 31, 2015	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income Tax Expense (Benefit)	$ 16.7	[1]	$ 21.3	$ 269.5	[2]	$ 2.7	$ (18.6)	$ 0.9	$ 11.6	$ 7.3		$ 310.2	$ 1.2	$ 51.1
Diluted net (loss) income per share (usd per share)	$ (0.17)	[1]	$ (0.19)	$ (1.18)	[2]	$ 0.08	$ 0.05	$ 0.05	$ 0.13	$ 0.12		$ (1.46)	$ 0.35	$ 1.00
Operating Expenses												$ 2,132.1	$ 2,049.4	$ 1,714.8
(Decrease) to general and administrative													(10.9)	(36.5)
Increase to amortization of purchased intangibles													$ 10.9	$ 36.5
Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income Tax Expense (Benefit)				$ 33.1							$ 33.1
Scenario, Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Diluted net (loss) income per share (usd per share)	$ (0.15)											$ (1.44)
Additional Foreign Withholding Taxes | Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Income Tax Expense (Benefit)	$ (4.5)
Employee Benefits and Estimated Personal Property Liabilities
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Operating Expenses												$ 5.7

[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.