Fair Value Measurements - Narrative (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			3 Months Ended			12 Months Ended		3 Months Ended
	Oct. 31, 2014		Oct. 31, 2013	Apr. 30, 2014	Oct. 31, 2013		Oct. 31, 2012		Apr. 30, 2013	Oct. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill	$ 38		$ 184		$ 184		$ 280			$ 319
Cash and Cash Equivalents, Maturity Term	90 days
Marketable Securities, Maturity Term	90 days
Indefinite-Lived Intangible Assets (Excluding Goodwill)	34		46		46
Impairment of Long-Lived Assets Held-for-use			20
Goodwill, Impairment Loss	142		81
Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment and Intangible Assets, Fair Value Disclosure			25		25
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Property, Plant, and Equipment, Fair Value Disclosure			5		5
Brazilian Reporting Unit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill				142
Indefinite-Lived Intangible Assets (Excluding Goodwill)				43
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	7			7	0		0
Goodwill, Impairment Loss	142	[1]			81	[1]	0	[1]
North America Truck [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Goodwill	0		0		0		82			82
Goodwill, Impairment Loss	$ 0		$ 81		$ (77)				$ (4)

[1] (A)For more information, see Note 8, Goodwill and Other Intangible Assets, Net, and includes $4 million related to discontinued operations in 2013.