Post Retirement Benefit Plans - Weighted Average Asset Allocations at Measurement Date and Target Asset Allocations (Detail)	12 Months Ended
	Oct. 31, 2016	Oct. 31, 2015
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total, Target	100.00%	100.00%
Total, Actual	100.00%	100.00%
Equity securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total, Target	25.00%	23.00%
Total, Actual	29.00%	28.00%
Debt securities
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total, Target	49.00%	51.00%
Total, Actual	40.00%	40.00%
Other
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total, Target	26.00%	26.00%
Total, Actual	31.00%	32.00%