Restructuring Charges - Reconciliation of Beginning and Ending Restructuring Reserve Balances (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Restructuring Reserve [Roll Forward]
Beginning balance			$ 21.3
Costs incurred and charged to expense	$ 10.2	$ 16.2	17.9	$ 26.7
Costs paid or otherwise settled			(24.4)
Ending balance	14.8		14.8
Employee Separation Costs
Restructuring Reserve [Roll Forward]
Beginning balance			14.7
Costs incurred and charged to expense	5.3		10.7
Costs paid or otherwise settled			(16.6)
Ending balance	8.8		8.8
Other Costs
Restructuring Reserve [Roll Forward]
Beginning balance			6.6
Costs incurred and charged to expense	4.9		7.2
Costs paid or otherwise settled			(7.8)
Ending balance	$ 6.0		$ 6.0