Postretirement Benefits - Expected Future Benefit Costs (Details) $ in Millions	Oct. 31, 2015 USD ($)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	$ 304
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	298
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	292
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	285
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	280
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	1,288
Health and Life Insurance Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	129
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	121
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	123
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	122
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	121
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	$ 586