Leases - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Jul. 31, 2020	Jul. 31, 2020
Operating lease costs:
Operating lease, cost	$ 21.0	$ 72.2
Finance lease costs:
Operating expenses(4)	1.2	3.3
Interest expense(5)	0.1	0.4
Total lease costs	22.3	75.9
Short-term lease costs	9.5	35.9
Variable lease costs	0.0	3.0
Total short-term and variable lease costs	9.5	38.9
Operating expenses(1)(2)
Operating lease costs:
Operating lease, cost	14.8	52.9
Selling, general and administrative expenses(3)
Operating lease costs:
Operating lease, cost	$ 6.2	$ 19.3