Summary of Significant Accounting Policies - Narrative (Details) $ in Millions	3 Months Ended						9 Months Ended
	Jul. 31, 2020 USD ($) segments	Apr. 30, 2020 USD ($) employees	Jan. 31, 2020 USD ($)	Jul. 31, 2019 USD ($)	Apr. 30, 2019 USD ($)	Jan. 31, 2019 USD ($)	Jul. 31, 2020 USD ($) segments	Jul. 31, 2019 USD ($)	Oct. 31, 2019 USD ($)
Accounting Policies [Line Items]
Document Period End Date							Jul. 31, 2020
Selling, General and Administrative Expense	$ (141)			$ (167)			$ (493)	$ (726)
Net Cash Provided by (Used in) Investing Activities							(167)	(9)
Sales of Manufactured Products	1,639			2,996			5,310	8,330
Accounts Receivable, after Allowance for Credit Loss, Current	(266)						(266)		$ (338)
Property and equipment, net	(1,241)						(1,241)		(1,309)
Liabilities, Current	(3,115)						(3,115)		(3,575)
Long-term Debt and Lease Obligation	(4,694)						(4,694)		(4,317)
Other Liabilities, Noncurrent	681						681		645
Liabilities	(10,503)						(10,503)		(10,640)
Assets	(6,675)						(6,675)		(6,917)
Debt, Current	(865)						(865)		(871)
Other Liabilities, Current	1,096						1,096		1,363
Cost of Goods and Services Sold	$ (1,388)			(2,501)			$ (4,541)	(6,973)
Number Of Segments | segments	4						4
Goodwill	$ 38						$ 38		38
Interest expense	(71)			(76)			(199)	(243)
Income (Loss) Attributable to Parent, before Tax	(26)			190			(89)	144
Capital expenditures	25			24			115	90
Proceeds from finance lease obligations							0	13
Product Warranty Accrual, Preexisting, Increase (Decrease)							$ 26	7
Document Type							10-Q
Inventory, Gross	200						$ 200
Tax expense	(8)			(29)			(10)	(9)
Stockholders' Equity Attributable to Parent	(3,830)						(3,830)		(3,726)
Inventory, Net	(896)						(896)		(911)
Other Assets, Current	247						247		277
Assets, Current	4,692						4,692		4,952
Other Assets, Noncurrent	(108)						(108)		(107)
Liabilities and Equity	(6,675)						(6,675)		(6,917)
Other expense, net	14			25			27	140
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(34)	$ (33)	$ (32)	161	$ (43)	$ 17	(99)	135
Unionized Employees Concentration Risk [Member] | Number Of Employees Hourly Workers [Member]
Accounting Policies [Line Items]
Concentration Risk Number Of Employees | employees		6,600
concentration risk number of employees percentage		97.00%
Unionized Employees Concentration Risk [Member] | Number of Employees Salaried Workers [Member]
Accounting Policies [Line Items]
Concentration Risk Number Of Employees | employees		700
concentration risk number of employees percentage		13.00%
Traton Group [Member]
Accounting Policies [Line Items]
Less: Intercompany revenues	29			42			72	113
Costs and Expenses, Related Party	13			11			37	29
Accounts Receivable, Related Parties	7						7		13
Accounts Payable, Related Parties	84						84		55
Navistar Defense [Member]
Accounting Policies [Line Items]
Less: Intercompany revenues	12			9			37	43
Accounts Receivable, Related Parties	27						27		29
North America Truck [Member]
Accounting Policies [Line Items]
Assets	(1,721)						(1,721)		$ (1,705)
Interest expense	0			0			0	0
Capital expenditures	18			17			93	69
Tax expense	$ 0			$ 0			$ 0	$ 0