Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Disaggregation of Revenue [Line Items]
Finance revenues			$ 48	$ 40	$ 95	$ 78
Sales and revenues, net			2,996	2,422	5,429	4,327
Operating lease revenue			1
Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			2,102		3,782
Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			112		130
Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			46		97
Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			138		249
Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			521		1,018
Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			29	27	58	56
Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			2,948		5,334
Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			36		71
Interest income			14	27
Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			12		24
Interest income			12			24
Third-Party Financings [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			2		5
Military Sales [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net		$ 62
North America Truck [Member]
Disaggregation of Revenue [Line Items]
Sales and revenues, net			2,287		4,063
North America Truck [Member] | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			2,099		3,776
North America Truck [Member] | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			112		130
North America Truck [Member] | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			46		97
North America Truck [Member] | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
North America Truck [Member] | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			1		2
North America Truck [Member] | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			29		58
North America Truck [Member] | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			2,287		4,063
North America Truck [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0		0
North America Truck [Member] | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0		0
North America Parts [Member]
Disaggregation of Revenue [Line Items]
Sales and revenues, net			578		1,124
North America Parts [Member] | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
North America Parts [Member] | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
North America Parts [Member] | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
North America Parts [Member] | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			78		144
North America Parts [Member] | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			500		980
North America Parts [Member] | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
North America Parts [Member] | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			578		1,124
North America Parts [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0		0
North America Parts [Member] | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0		0
Global Operations [Member]
Disaggregation of Revenue [Line Items]
Sales and revenues, net			80		141
Global Operations [Member] | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Global Operations [Member] | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Global Operations [Member] | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Global Operations [Member] | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			60		105
Global Operations [Member] | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			20		36
Global Operations [Member] | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Global Operations [Member] | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			80		141
Global Operations [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0		0
Global Operations [Member] | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0		0
Financial Services Operations
Disaggregation of Revenue [Line Items]
Finance revenues			48	$ 40	95	$ 78
Sales and revenues, net			48		95
Financial Services Operations | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Financial Services Operations | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Financial Services Operations | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Financial Services Operations | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Financial Services Operations | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Financial Services Operations | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Financial Services Operations | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Financial Services Operations | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			36		71
Financial Services Operations | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			12		24
Corporate And Eliminations [Member]
Disaggregation of Revenue [Line Items]
Sales and revenues, net			3		6
Corporate And Eliminations [Member] | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			3		6
Corporate And Eliminations [Member] | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Corporate And Eliminations [Member] | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Corporate And Eliminations [Member] | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Corporate And Eliminations [Member] | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Corporate And Eliminations [Member] | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0		0
Corporate And Eliminations [Member] | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			3		6
Corporate And Eliminations [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0		0
Corporate And Eliminations [Member] | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			$ 0		$ 0
Navistar Defense [Member]
Disaggregation of Revenue [Line Items]
Equity Interest, Percent Sold	70.00%