Stockholders' Deficit - Narrative (Details) - USD ($) shares in Millions, $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Aug. 31, 2017	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Stockholders' Equity Note [Abstract]
Repurchases of common stock (shares)		16	4	55	100
Subsequent Event [Line Items]
Payment in connection with repurchases of shares		$ 300	$ 100	$ 911	$ 1,159
Share repurchase authorization remaining		$ 3,000		$ 3,000
Subsequent event
Subsequent Event [Line Items]
Share repurchases that will be settled in subsequent period (shares)	0