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, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Disaggregation of Revenue [Line Items]
Finance revenues			$ 48	$ 48	$ 92	$ 95
Sales and revenues, net			1,925	2,996	3,763	5,429
Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			1,260	2,102	2,338	3,782
Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			59	112	156	130
Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			42	46	83	97
Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			85	138	182	249
Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			405	521	861	1,018
Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			26	29	51	58
Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			1,877	2,948	3,671	5,334
Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			39	36	74	71
Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			9	12	18	24
Interest income			8	12	18	24
Military Sales [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net		$ 62
Finance Revenue, Net [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			48	48	92	95
North America Truck [Member]
Disaggregation of Revenue [Line Items]
Sales and revenues, net			1,385	2,287	2,623	4,063
North America Truck [Member] | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			1,257	2,099	2,332	3,776
North America Truck [Member] | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			59	112	156	130
North America Truck [Member] | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			42	46	83	97
North America Truck [Member] | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
North America Truck [Member] | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			1	1	1	2
North America Truck [Member] | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			26	29	51	58
North America Truck [Member] | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			1,385	2,287	2,623	4,063
North America Truck [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
North America Truck [Member] | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
North America Truck [Member] | Finance Revenue, Net [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
North America Parts [Member]
Disaggregation of Revenue [Line Items]
Sales and revenues, net			442	578	934	1,124
North America Parts [Member] | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
North America Parts [Member] | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
North America Parts [Member] | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
North America Parts [Member] | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			49	78	99	144
North America Parts [Member] | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			393	500	835	980
North America Parts [Member] | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
North America Parts [Member] | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			442	578	934	1,124
North America Parts [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
North America Parts [Member] | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
North America Parts [Member] | Finance Revenue, Net [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
Global Operations [Member]
Disaggregation of Revenue [Line Items]
Sales and revenues, net			47	80	108	141
Global Operations [Member] | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Global Operations [Member] | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Global Operations [Member] | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Global Operations [Member] | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			36	60	83	105
Global Operations [Member] | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			11	20	25	36
Global Operations [Member] | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Global Operations [Member] | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			47	80	108	141
Global Operations [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
Global Operations [Member] | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
Global Operations [Member] | Finance Revenue, Net [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
Financial Services Operations
Disaggregation of Revenue [Line Items]
Finance revenues			50	48	96	95
Sales and revenues, net			50	48	96	95
Interest Revenue (Expense), Net			40	55	75	108
Financial Services Operations | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Financial Services Operations | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Financial Services Operations | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Financial Services Operations | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Financial Services Operations | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Financial Services Operations | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Financial Services Operations | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Financial Services Operations | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			41	36	78	71
Interest Revenue (Expense), Net			17	14	32	27
Financial Services Operations | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			9	12	18	24
Financial Services Operations | Finance Revenue, Net [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			50	48	96	95
Corporate And Eliminations [Member]
Disaggregation of Revenue [Line Items]
Sales and revenues, net			1	3	2	6
Corporate And Eliminations [Member] | Truck products and services [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			3	3	6	6
Corporate And Eliminations [Member] | Truck contract manufacturing [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Corporate And Eliminations [Member] | Used Trucks [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Corporate And Eliminations [Member] | Engines [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Corporate And Eliminations [Member] | Parts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Corporate And Eliminations [Member] | Extended warranty contracts [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			0	0	0	0
Corporate And Eliminations [Member] | Manufactured products, net [Member]
Disaggregation of Revenue [Line Items]
Sales of manufactured products, net			3	3	6	6
Corporate And Eliminations [Member] | Retail [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			(2)	0	(4)	0
Corporate And Eliminations [Member] | Wholesale financing [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			0	0	0	0
Corporate And Eliminations [Member] | Finance Revenue, Net [Member]
Disaggregation of Revenue [Line Items]
Finance revenues			$ (2)	$ 0	$ (4)	$ 0
Navistar Defense [Member]
Disaggregation of Revenue [Line Items]
Equity Interest, Percent Sold	70.00%