Postretirement Benefits - Narrative (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Jul. 31, 2017	Jan. 31, 2017	Jul. 31, 2016	Jul. 31, 2014	Jul. 31, 2017	Jul. 31, 2016	Oct. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 21		$ 20		$ 67	$ 60
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year					46
Defined Benefit Plan, Cost of Providing Special or Contractual Termination Benefits Recognized During Period		$ 1
Income Tax Expense (Benefit)	0		14		10	25
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	2,747				2,747		$ 3,023
Defined Contribution Plan, Cost Recognized	7		$ 7		22	$ 22
Chatham [Member] | Facility Closing [Member] | Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Postemployment Benefits, Period Expense	23	$ 6		$ 14
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	(66)				$ (66)
Melrose Park [Member] | Facility Closing [Member] | Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Postemployment Benefits, Period Expense	41
Defined Benefit Plan, Actuarial Gain (Loss)	91
Melrose Park [Member] | Defined Benefit Plan Remeasurement [Domain] | Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Postemployment Benefits, Period Expense	2
Intraperiod Tax Allocation Rule [Member]
Defined Benefit Plan Disclosure [Line Items]
Income Tax Expense (Benefit)	$ (35)