Leases Leases (Lease Costs and Cash Flow Information) (Details) $ in Millions	12 Months Ended
	Jan. 31, 2020 USD ($)
Operating lease, cost	$ 86.8
Variable lease, cost	12.2
Operating lease, payments	93.5
Right-of-use asset obtained in exchange for operating lease liability	231.7
Variable lease, payment	12.2
Cost of subscription and maintenance revenue
Operating lease, cost	6.6
Variable lease, cost	0.9
Cost of other revenue
Operating lease, cost	2.2
Variable lease, cost	0.3
Marketing and sales
Operating lease, cost	38.0
Variable lease, cost	5.4
Research and development
Operating lease, cost	27.3
Variable lease, cost	3.8
General and administrative
Operating lease, cost	12.7
Variable lease, cost	$ 1.8