Restructuring Charges - Reconciliation of Beginning and Ended Restructuring Reserve Balances (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Restructuring Reserve [Roll Forward]
Beginning balance			$ 4.4	$ 5.2
Costs incurred and charged to expense	$ 5.8	$ 4.8	26.1	18.6	$ 12.7
Costs paid or otherwise settled			(19.2)	(19.4)
Ending balance	11.3	4.4	11.3	4.4	5.2
Employee Separation Costs
Restructuring Reserve [Roll Forward]
Beginning balance			4.2	3.9
Costs incurred and charged to expense			22.5	14.8	9.0
Costs paid or otherwise settled			(17.2)	(14.5)
Ending balance	9.5	4.2	9.5	4.2	3.9
Other Costs
Restructuring Reserve [Roll Forward]
Beginning balance			0.2	1.3
Costs incurred and charged to expense			3.6	3.8	3.7
Costs paid or otherwise settled			(2.0)	(4.9)
Ending balance	$ 1.8	$ 0.2	$ 1.8	$ 0.2	$ 1.3