Summary of Significant Accounting Policies - Product Warranty Liability (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended				6 Months Ended			3 Months Ended
	Apr. 30, 2013	Jan. 31, 2013	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014 NA Truck [Member]	Apr. 30, 2013 NA Truck [Member]	Apr. 30, 2014 Extended Warranty Programs [Member]	Apr. 30, 2013 Extended Warranty Programs [Member]	Apr. 30, 2014 Extended Warranty Programs [Member]	Apr. 30, 2013 Extended Warranty Programs [Member]	Oct. 31, 2013 Extended Warranty Programs [Member]	Apr. 30, 2014 Product Warranty Accrual [Member]	Jan. 31, 2014 Product Warranty Accrual [Member]	Apr. 30, 2013 Product Warranty Accrual [Member]	Jan. 31, 2013 Product Warranty Accrual [Member]	Jan. 31, 2013 recoverable [Member]
Accrued Product Warranty And Deferred Warranty Revenue, Standard And Extended Warranty Programs, Roll Forward:
Balance at beginning of period		$ 1,118	$ 1,349	$ 1,118
Costs accrued and revenues deferred			153	226
Currency translation adjustment			(1)	0
Adjustments to pre-existing warranties(A)(B)			94	204								42	52	164	40	13
Payments and revenues recognized			(272)	(327)
Balance at end of period	1,221		1,323	1,221
Less: Current portion	647		626	647
Noncurrent accrued product warranty and deferred warranty revenue	574		697	574
Product Warranty Accrual, Preexisting Increase Decrease Per Share, Net of Tax												$ 0.52	$ 0.64	$ 2.04	$ 0.50
Warranty Recoveries	13	27
Extended Warranty Program:
Deferred Revenue, Revenue Recognized							33	11	60	40
Deferred Revenue							437		437		420
Product Warranty Expense					$ 34	$ 33