Postretirement Benefits - Schedule of Net Benefit (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ (2)	$ (2)
Interest on obligations	27	30
Amortization of cumulative loss	29	26
Contractual termination benefits	1	0
Premiums on pension insurance	4	4
Expected return on assets	(40)	(42)
Net postretirement benefits expense	23	20
Health and Life Insurance Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	(1)	(1)
Interest on obligations	12	15
Amortization of cumulative loss	6	8
Contractual termination benefits	0	0
Premiums on pension insurance	0	0
Expected return on assets	(6)	(6)
Net postretirement benefits expense	$ 13	$ 18