Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2017	Oct. 31, 2016	Jan. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset impairment charges	$ 2		$ 2
Goodwill	$ 38	$ 38
Cash and Cash Equivalents, Maturity Term		90 days
Marketable Securities, Maturity Term		90 days