Leases - Lease Impact on Balance Sheet (Details) - USD ($) $ in Millions	6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019
Leases [Abstract]
Cash flows from operating activities attributable to operating leases	$ 146.8	$ 147.8
Right-of-use assets obtained in exchange for operating lease liabilities	$ 127.6	$ 144.9