Income Taxes - Income Taxes Differences between the U.S. statutory rate and the aggregate income tax provision (Details) - USD ($) $ 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
Income Tax Disclosure [Abstract]
Income tax provision at U.S. Federal statutory rate											$ (7.1)	$ 29.0	$ 98.0
State income tax benefit, net of the U.S. Federal benefit											(7.6)	(4.0)	(2.9)
Foreign income taxed at rates different from the U.S. statutory rate											(29.4)	(40.0)	(57.1)
U.S. valuation allowance											345.0	2.9	2.1
Tax effect of non-deductible stock-based compensation											19.3	15.7	10.8
Research and development tax credit benefit											(9.4)	(7.2)	(8.8)
Closure of income tax audits and changes in uncertain tax positions											(4.7)	(0.7)	3.6
Tax effect of officer compensation in excess of $1.0 million											1.4	2.4	3.0
Non-deductible expenses											2.6	2.2	2.6
Other											0.1	0.9	(0.2)
Income tax expense	$ 16.7		$ 21.3	$ 269.5		$ 2.7	$ (18.6)	$ 0.9	$ 11.6	$ 7.3	$ 310.2	$ 1.2	$ 51.1

[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.