Restructuring Charges - Reconciliation of Beginning and Ended Restructuring Reserve Balances (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2014
Restructuring Reserve [Roll Forward]
Beginning balance			$ 21.3	$ 4.1
Costs incurred and charged to expense	$ 9.0	$ 13.3	26.9	40.0	$ 16.1
Costs paid or otherwise settled			(37.8)	(22.8)
Ending balance	10.4	21.3	10.4	21.3	4.1
Employee Separation Costs
Restructuring Reserve [Roll Forward]
Beginning balance			14.7	2.9
Costs incurred and charged to expense			16.7	27.8	12.0
Costs paid or otherwise settled			(22.2)	(16.0)
Ending balance	9.2	14.7	9.2	14.7	2.9
Other costs
Restructuring Reserve [Roll Forward]
Beginning balance			6.6	1.2
Costs incurred and charged to expense			10.2	12.2	4.1
Costs paid or otherwise settled			(15.6)	(6.8)
Ending balance	$ 1.2	$ 6.6	$ 1.2	$ 6.6	$ 1.2