Postretirement Benefits - Components of Postretirement Benefits Included in Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Net postretirement benefits expense	$ 150	$ 160	$ 177
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Net postretirement benefits expense	69	106	116
Health and Life Insurance Benefits
Defined Benefit Plan Disclosure [Line Items]
Net postretirement benefits expense	$ 81	$ 54	$ 61