Summary of Significant Accounting Policies - Product Warranty Liability (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended										12 Months Ended
	Oct. 31, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2012
Product Liability Contingency [Line Items]
Product Warranty Accrual	$ 994		$ 1,197				$ 1,349				$ 994	$ 1,197	$ 1,349	$ 1,118
Product Warranty Accrual, Warranties Issued											190	302	469
Product Warranty Accrual, Divestures											0	0	(3)
Product Warranty Accrual, Currency Translation, Increase (Decrease)											(9)	(4)	(2)
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Adjustments to pre-existing warranties(A)(B)	40		(10)				152				1	55	404
Warranty Recoveries									$ 13	$ 27
Extended Warranty Program:
Product Warranty Accrual, Payments											(385)	(505)	(637)
Product Warranty Accrual, Current	429		535				601				429	535	601
Product Warranty Accrual, Noncurrent	565		662				748				565	662	748
North America Truck [Member]
Extended Warranty Program:
Product Warranty Expense													161
Extended Warranty Programs [Member]
Extended Warranty Program:
Deferred Revenue, Revenue Recognized											154	132	87
Deferred Revenue	$ 401		$ 437				$ 420				401	$ 437	420
recoverable [Member]
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Adjustments to pre-existing warranties(A)(B)										13
Product Warranty Accrual [Member]
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Adjustments to pre-existing warranties(A)(B)		$ (57)		$ (29)	$ 42	$ 52		$ 48	$ 164	$ 40
Product Warranty Accrual, Preexisting Increase Decrease Per Share, Net of Tax	$ 0.49	$ (0.70)		$ (0.36)	$ 0.52	$ 0.64	$ 1.89	$ 0.60	$ 2.04	$ 0.50
Discontinued Operations [Member] | Product Warranty Accrual [Member]
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Adjustments to pre-existing warranties(A)(B)											$ (3)
Pre-existing Warranty [Member] | North America Truck [Member]
Extended Warranty Program:
Product Warranty Expense													$ 127