Post Retirement Benefit Plans - Components of Net Periodic Cost for Postretirement Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 12.4	$ 15.5	$ 15.7
Interest cost	22.0	27.6	29.6
Amortization of prior service cost	(0.2)	0.1	0.2
Net periodic pension (benefit) cost	13.6	25.3	22.0
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.0	0.0	0.0
Interest cost	0.5	0.7	0.8
Amortization of prior service cost	(1.5)	(1.5)	(1.6)
Recognized net actuarial gain	(0.1)	(0.1)	0.0
Net periodic pension (benefit) cost	$ (1.1)	$ (0.9)	$ (0.8)