Business and Summary of Significant Accounting Policies Business and Summary of Significant Accounting Policies Additional Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011	Jan. 31, 2010
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 400.0
Total sales to the distributors Tech Data Corporation and its global affiliates ("Tech Data") relative to Autodesk's consolidated net revenue	17.00%	16.00%	14.00%
Concentration Risk, Percentage	21.00%	22.00%	21.00%
Depreciation, Nonproduction	43.7	47.6	50.4
Finite-Lived Intangible Assets, Useful Life, Minimum	2
Finite-Lived Intangible Assets, Useful Life, Maximum	7
Finite-Lived Intangible Assets, Amortization Expense	71.8	57.8	61.2
Cumulative error from the understatement of stock-based compensation, net of tax effects			6.8
Advertising Expense	21.3	18.8	18.4
Purchased Technologies, Customer Relationships and Trade Names
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Acquired Finite-lived Intangible Asset, Weighted Average Useful Life	5.4
Cost of Sales
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Cumulative error from the understatement of stock-based compensation, net of tax effects			0.4
Selling and Marketing Expense
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Cumulative error from the understatement of stock-based compensation, net of tax effects			4.4
Other Research and Development Expense
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Cumulative error from the understatement of stock-based compensation, net of tax effects			2.9
General and Administrative Expense
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Cumulative error from the understatement of stock-based compensation, net of tax effects			2.1
Reduction in Taxes
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Cumulative error from the understatement of stock-based compensation, net of tax effects			3.0
Accounts Receivable
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Concentration Risk, Percentage	21.00%	16.00%
Media and Entertainment
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Goodwill, Impairment Loss			$ 21.0