Restructuring Charges - Reconciliation of Beginning and Ended Restructuring Reserve Balances (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Restructuring Reserve [Roll Forward]
Beginning balance			$ 11.3	$ 4.4
Costs incurred and charged to expense	$ 11.9	$ 5.8	38.7	26.1	$ 18.6
Costs paid or otherwise settled			(28.4)	(19.2)
Ending balance	21.6	11.3	21.6	11.3	4.4
Employee Separation Costs
Restructuring Reserve [Roll Forward]
Beginning balance			9.5	4.2
Costs incurred and charged to expense			26.4	22.5	14.8
Costs paid or otherwise settled			(18.0)	(17.2)
Ending balance	17.9	9.5	17.9	9.5	4.2
Other Costs
Restructuring Reserve [Roll Forward]
Beginning balance			1.8	0.2
Costs incurred and charged to expense			12.3	3.6	3.8
Costs paid or otherwise settled			(10.4)	(2.0)
Ending balance	$ 3.7	$ 1.8	$ 3.7	$ 1.8	$ 0.2