Postretirement Benefits - Schedule of Net Benefit (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2016	Jan. 31, 2015
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 3
Interest on obligations	30	36
Amortization of cumulative loss	26	25
Amortization of cumulative loss	0	0
Premiums on pension insurance	4	1
Expected return on assets	(42)	(49)
Net postretirement benefits expense	20	16
Health and Life Insurance Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest on obligations	15	18
Amortization of cumulative loss	8	10
Amortization of cumulative loss	0	(1)
Premiums on pension insurance	0	0
Expected return on assets	(6)	(7)
Net postretirement benefits expense	$ 18	$ 21