Retirement, pension and other postretirement plans (Details 13)	12 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Oct. 31, 2009
Postretirement Benefit Plans United States [Member]
Assumptions used to determine benefit obligations at October 31:
Discount rate	4.50%	5.25%	5.50%
Health care cost trend rate	9.36%	9.00%	8.25%
Rate to which health care cost trend rate is assumed to decline (ultimate trend rate)	5.00%	5.00%	4.50%
Year the rate reaches the ultimate trend rate	2016	2020	2015
Assumptions used to determine net benefit costs for the years ended October 31:
Discount rate	5.25%	5.50%	8.00%
Postretirement Benefit Plans International [Member]
Assumptions used to determine benefit obligations at October 31:
Discount rate	5.85%	5.75%	6.75%
Health care cost trend rate	7.00%	6.80%	7.50%
Rate to which health care cost trend rate is assumed to decline (ultimate trend rate)	3.50%	4.80%	4.80%
Year the rate reaches the ultimate trend rate	2031	2013	2013
Assumptions used to determine net benefit costs for the years ended October 31:
Discount rate	5.75%	6.75%	7.70%