Restructuring and Impairments - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2018	Oct. 31, 2018	Jul. 31, 2018	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges				$ 2,000,000	$ 12,000,000	$ (1,000,000)
Costs of products sold				6,221,000,000	9,245,000,000	8,317,000,000
Liability, Defined Benefit Plan, Noncurrent				1,705,000,000	2,103,000,000
Asset impairment charges				28,000,000	7,000,000	14,000,000
Gain on sales of investments and businesses, net				0	56,000,000	0
Global Operations [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 1,000,000		5,000,000	11,000,000
Global Operations [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Costs of products sold					3,000,000
North America Truck [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges				7,000,000
Navistar Defense [Member]
Restructuring Cost and Reserve [Line Items]
Equity Interest, Percent Sold	70.00%
Proceeds from Divestiture of Businesses	$ 140,000,000
Gain on sales of investments and businesses, net	$ 51,000,000
Other Postretirement Benefits Plan [Member]
Restructuring Cost and Reserve [Line Items]
Liability, Defined Benefit Plan, Noncurrent				337,000,000	784,000,000
Property Subject to Operating Lease [Member] | North America Truck [Member]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges				10,000,000	6,000,000	5,000,000
long-lived asset [Domain] | Global Operations [Member]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges				12,000,000
long-lived asset [Domain] | North America Truck [Member]
Restructuring Cost and Reserve [Line Items]
Asset impairment charges			$ 2,000,000	$ 6,000,000	$ 1,000,000	6,000,000
long-lived asset [Domain] | Financial Services Operations
Restructuring Cost and Reserve [Line Items]
Asset impairment charges						$ 1,000,000