Summary of Significant Accounting Policies - Product Warranty Liability (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended						12 Months Ended
	Apr. 30, 2016	Oct. 31, 2015	Jan. 31, 2015	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2013
Product Liability Contingency [Line Items]
Document Type							10-K
Product Warranty Accrual		$ 994					$ 818	$ 994	$ 1,197	$ 1,349
Product Warranty Accrual, Warranties Issued							186	260	354
Product Warranty Accrual, Currency Translation, Increase (Decrease)							3	(9)	(4)
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Adjustments to pre-existing warranties(A)(B)							77	1	55
Extended Warranty Program:
Product Warranty Accrual, Payments							(442)	(455)	(557)
Product Warranty Accrual, Current		429					396	429	535
Product Warranty Accrual, Noncurrent		565					422	565	662
North America Truck [Member]
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Product Warranty Expense							34	56
Extended Warranty Programs [Member]
Extended Warranty Program:
Deferred Revenue, Revenue Recognized							150	154	132
Deferred Revenue		401					325	401	437
Product Warranty Costs Accrued And Revenues Deferred And Payments And Revenues Recognized
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Prior Period Reclassification Adjustment							36
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)	$ 46	$ 40	$ (57)	$ (29)	$ 42	$ 52
Product Warranty Accrual, Preexisting Increase Decrease Per Share, Net of Tax	$ 0.56	$ 0.49	$ (0.70)	$ (0.36)	$ 0.52	$ 0.64
Amortization of Loss Reserves [Member]
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Prior Period Reclassification Adjustment								34	52
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)							(1)	(3)
Field Campaign to address issues in products sold [Member] | North America Truck [Member]
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Product Warranty Expense							17	12	$ 13
Pre-existing Warranty [Member] | North America Truck [Member]
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Product Warranty Expense							$ 26	$ 54
Minimum [Member]
Product Liability Contingency [Line Items]
Product Warranty Coverage Period							1 year
Maximum [Member]
Product Liability Contingency [Line Items]
Product Warranty Coverage Period							5 years