Postretirement Benefits - Schedule of Net Benefit (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost	$ 7	$ 6
Employer contributions	21	22
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2
Interest on obligations	27	27
Amortization of cumulative loss	26	29
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	9	0
Contractual termination benefits	0	1
Premiums on pension insurance	2	4
Expected return on assets	(40)	(40)
Net postretirement benefits expense	26	23
Health and Life Insurance Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1
Interest on obligations	11	12
Amortization of cumulative loss	2	6
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	0	0
Contractual termination benefits	0	0
Premiums on pension insurance	0	0
Expected return on assets	(6)	(6)
Net postretirement benefits expense	$ 8	$ 13