Revenue Recognition - Contract Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020
Disaggregation of Revenue [Line Items]
Net revenue	$ 1,059.7	$ 913.1	$ 2,049.0	$ 1,798.8
Design
Disaggregation of Revenue [Line Items]
Net revenue	944.0	821.4	1,829.1	1,619.1
Make
Disaggregation of Revenue [Line Items]
Net revenue	89.6	71.0	171.1	138.4
Other
Disaggregation of Revenue [Line Items]
Net revenue	26.1	20.7	48.8	41.3
Indirect
Disaggregation of Revenue [Line Items]
Net revenue	702.2	639.3	1,363.5	1,262.7
Direct
Disaggregation of Revenue [Line Items]
Net revenue	357.5	273.8	685.5	536.1
Americas
Disaggregation of Revenue [Line Items]
Net revenue	422.8	371.5	814.5	733.7
U.S.
Disaggregation of Revenue [Line Items]
Net revenue	347.3	309.5	671.3	610.1
Other Americas
Disaggregation of Revenue [Line Items]
Net revenue	75.5	62.0	143.2	123.6
Europe, Middle East, and Africa
Disaggregation of Revenue [Line Items]
Net revenue	410.2	354.7	792.7	699.5
Asia Pacific
Disaggregation of Revenue [Line Items]
Net revenue	226.7	186.9	441.8	365.6
Architecture, Engineering and Construction
Disaggregation of Revenue [Line Items]
Net revenue	478.7	397.0	921.3	779.7
AutoCAD and AutoCAD LT
Disaggregation of Revenue [Line Items]
Net revenue	304.4	271.9	589.5	534.1
Manufacturing
Disaggregation of Revenue [Line Items]
Net revenue	207.7	185.5	405.0	368.4
Media and Entertainment
Disaggregation of Revenue [Line Items]
Net revenue	58.5	53.3	113.5	105.9
Other
Disaggregation of Revenue [Line Items]
Net revenue	$ 10.4	$ 5.4	$ 19.7	$ 10.7