Stockholders' Equity - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 31, 2020	Jan. 28, 2020	Jan. 31, 2019
Stockholders Equity Note [Line Items]
Share repurchase program					$ 8,500,000,000
January 2019 share repurchase program remaining authorized funds	$ 1,700,000,000
Cash dividends declared and paid, at a quarterly amount per Class A share	$ 671,000,000	$ 572,000,000
Subsequent Event
Stockholders Equity Note [Line Items]
Additional share repurchase program			$ 9,500,000,000
Subsequent Event | Class A common stock
Stockholders Equity Note [Line Items]
Quarterly cash dividend (in dollars per share)				$ 0.30