Segment Reporting - Narrative (Details) $ in Millions	3 Months Ended								12 Months Ended
	Oct. 31, 2020 USD ($)	Jul. 31, 2020 USD ($)	Apr. 30, 2020 USD ($)	Jan. 31, 2020 USD ($)	Oct. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)	Apr. 30, 2019 USD ($)	Jan. 31, 2019 USD ($)	Oct. 31, 2020 USD ($) segments	Oct. 31, 2019 USD ($)	Oct. 31, 2018 USD ($)
Segment Reporting [Abstract]
Concentration Risk, Customer										0	0
Segment Reporting Information [Line Items]
Number Of Segments | segments									4
Intersegment sales and revenues									$ 0	$ 0	$ 0
Sales and revenues, net	$ 2,065	$ 1,675	$ 1,925	$ 1,838	$ 2,780	$ 3,042	$ 2,996	$ 2,433	7,503	11,251	10,250
Financial Services Operations
Segment Reporting Information [Line Items]
Investment Income, Interest									130	208	182
Intersegment sales and revenues									40	104	97
Sales and revenues, net									217	297	257
North America Truck [Member]
Segment Reporting Information [Line Items]
Intersegment sales and revenues									72	84	104
Sales and revenues, net									5,312	8,585	7,490
North America Parts [Member]
Segment Reporting Information [Line Items]
Intersegment sales and revenues									5	6	8
Sales and revenues, net									1,846	2,245	2,407
Corporate And Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales and revenues									(128)	(228)	(264)
Sales and revenues, net									$ (125)	$ (219)	$ (264)