Stockholders' Deficit - Narrative (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
	Jun. 19, 2018	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Stockholders' Equity Note [Abstract]
Repurchases of common stock (shares)		26	31	92	86
Payment in connection with repurchases of shares		$ 500	$ 700	$ 1,944	$ 1,959
Share repurchase increase in authorization	$ 4,000
Remaining shares authorized for repurchase (shares)		$ 2,000		$ 2,000