Restructuring and Impairments - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended						9 Months Ended		12 Months Ended
	Dec. 31, 2018	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Jan. 31, 2018	Jul. 31, 2014	Jan. 31, 2014	Jul. 31, 2018	Jul. 31, 2017	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges										$ 12,000,000	$ (1,000,000)	$ 3,000,000
Costs of products sold										9,245,000,000	8,317,000,000	7,037,000,000
Liability, Defined Benefit Plan, Noncurrent			$ 2,097,000,000							2,103,000,000	2,097,000,000
Asset impairment charges										7,000,000	14,000,000	13,000,000
Pension Liability				$ 23,000,000
Restructuring Benefit				8,000,000
Inventory Reserve Charge				10,000,000
Gain on sales of investments and businesses, net										56,000,000	0	5,000,000
Global Operations [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges			6,000,000							11,000,000	1,000,000
Global Operations [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Costs of products sold										3,000,000
Navistar Financial Corporation [Member]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges								$ 1,000,000
Melrose Park [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 2,000,000		$ 41,000,000
Navistar Defense [Member]
Restructuring Cost and Reserve [Line Items]
Equity Interest, Percent Sold	70.00%
Proceeds from Divestiture of Businesses	$ 140,000,000
Potential Additional Consideration	17,000,000
Gain on sales of investments and businesses, net	$ 51,000,000
Huntsville Engine Plant [Member] | North America Truck [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges							$ 23,000,000
Other Postretirement Benefits Plan [Member]
Restructuring Cost and Reserve [Line Items]
Liability, Defined Benefit Plan, Noncurrent			$ 914,000,000							784,000,000	914,000,000
Other Postretirement Benefits Plan [Member] | Chatham [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Postemployment Benefits, Period Expense					$ 6,000,000	$ 14,000,000
Liability, Defined Benefit Plan, Noncurrent									$ 66,000,000
Cherokee [Domain]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges								2,000,000
Property Subject to Operating Lease [Member] | North America Truck [Member]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges										6,000,000	$ 5,000,000	$ 8,000,000
long-lived asset [Domain] | North America Truck [Member]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges								$ 6,000,000	$ 5,000,000	$ 1,000,000