Stockholders' Deficit - Narrative (Details) - USD ($)		1 Months Ended		3 Months Ended		9 Months Ended
	Feb. 20, 2020	Aug. 31, 2020	Aug. 31, 2019	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019	Feb. 22, 2020
Stockholders' Equity Note [Abstract]
Repurchases of common stock (shares)				59,000,000	26,000,000	97,000,000	92,000,000
Payment in connection with repurchases of shares				$ 1,000,000,000.0	$ 500,000,000	$ 1,767,000,000	$ 1,944,000,000
Authorized repurchase amount								$ 15,000,000,000.0
Share repurchase authorization remaining				$ 14,000,000,000.0		$ 14,000,000,000.0
Common stock dividends, preferred share purchase right declared (in shares)	1
Subsequent Event [Line Items]
Shares settled (in shares)			700,000
Subsequent event
Subsequent Event [Line Items]
Shares settled (in shares)		2,800,000