Stockholders' Deficit - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016
Stockholders' Equity Note [Abstract]
Repurchases of common stock (shares)	13	28	39	96
Share repurchases that will be settled in subsequent period (shares)	1
Payment in connection with repurchases of shares	$ 200	$ 300	$ 609	$ 1,102
Share repurchase authorization remaining	$ 3,300		$ 3,300