Retirement Plans and Postretirement Health Care and Life Insurance Benefits - Components of Net Periodic Cost for Postretirement Benefits (Detail) (Other Postretirement Benefit Plans, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014	Apr. 30, 2013
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost
Interest cost	0.2	0.2	0.4	0.4
Amortization of prior service cost and recognized actuarial gain	(0.4)	(0.4)	(0.8)	(0.8)
Net periodic benefit for postretirement benefits	$ (0.2)	$ (0.2)	$ (0.4)	$ (0.4)