Leases - Lease Cost in Statements of Earnings (Details) - USD ($) $ in Millions		3 Months Ended
		Apr. 30, 2020	Apr. 30, 2019
Lessee, Lease, Description [Line Items]
Fixed operating lease expense		$ 75.0	$ 77.3
Variable operating lease expense	[1]	10.5	34.6
Sublease income		(1.2)	(1.2)
Net lease expense		84.3	$ 110.7
Asia-Pacific | COVID-19
Lessee, Lease, Description [Line Items]
Rent concessions		$ 10.3

[1] Includes a credit of $10.3 million related to rent concessions negotiated in connection with retail store closures due to COVID-19.