Postretirement Benefits - Narrative (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jan. 31, 2017	Jul. 31, 2014	Jul. 31, 2018	Jul. 31, 2017	Oct. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		$ 21			$ 2
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits		9
Defined Contribution Plan, Administrative Expense		23			9
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment		10
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment		2
Income (Loss) from Continuing Operations before Income Taxes, Domestic		35
Defined Benefit Plan, Cost of Providing Special and Contractual Termination Benefits			$ 1
Liabilities	$ 11,258	66			11,258	$ 66	$ 10,709
Employer contributions	25	21			78	67
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	54				54
Income Tax Expense (Benefit)	3	0			25	10
Liability, Defined Benefit Plan, Noncurrent	2,378				2,378		$ 2,497
Defined Contribution Plan, Cost	7	7			25	22
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits		4
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	$ 0	58			$ 0	58
Chatham [Member] | Facility Closing [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Postemployment Benefits, Period Expense		23	$ 6	$ 14
Liability, Defined Benefit Plan, Noncurrent		66				$ 66
Melrose Park [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment		$ 91