Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended		9 Months Ended
	Jul. 19, 2024	May 08, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Jul. 23, 2024	May 06, 2024	Oct. 31, 2023	Sep. 30, 2023	Oct. 31, 2022
Equity, Class of Treasury Stock [Line Items]
Share repurchase program									$ 25,000		$ 12,000
Share repurchase programs authorized			$ 18,900		$ 18,900
Dividends paid			$ 1,056	$ 937	$ 3,200	$ 2,800
Preferred Stock
Equity, Class of Treasury Stock [Line Items]
Preferred stock, shares authorized (in shares)			25,000,000		25,000,000					25,000,000
Series A preferred stock
Equity, Class of Treasury Stock [Line Items]
Preferred stock, shares authorized (in shares)			4,000,000		4,000,000					4,000,000
Series B preferred stock
Equity, Class of Treasury Stock [Line Items]
Preferred stock, shares authorized (in shares)			2,000,000		2,000,000					2,000,000
Series C preferred stock
Equity, Class of Treasury Stock [Line Items]
Preferred stock, shares authorized (in shares)			3,000,000		3,000,000					3,000,000
Class A common stock
Equity, Class of Treasury Stock [Line Items]
Common stock, shares authorized (in shares)			2,000,000,000,000.0		2,000,000,000,000.0					2,000,000,000,000.0
Class B-1 common stock
Equity, Class of Treasury Stock [Line Items]
Stock tendered during period, shares, stock exchange offer (in shares)								241,000,000
Common stock, shares authorized (in shares)			499,000,000		499,000,000					622,000,000
Class B-2 common stock
Equity, Class of Treasury Stock [Line Items]
Stock issued during the period, new issues (in shares)		120,000,000
Common stock, shares authorized (in shares)			123,000,000		123,000,000
Class B-3 common stock
Equity, Class of Treasury Stock [Line Items]
Common stock, shares authorized (in shares)			61,000,000		61,000,000
Class B-4 common stock
Equity, Class of Treasury Stock [Line Items]
Common stock, shares authorized (in shares)			31,000,000		31,000,000
Class B-5 common stock
Equity, Class of Treasury Stock [Line Items]
Common stock, shares authorized (in shares)			15,000,000		15,000,000
Class C common stock
Equity, Class of Treasury Stock [Line Items]
Stock issued during the period, new issues (in shares)		48,000,000
Common stock, shares authorized (in shares)			1,100,000,000		1,100,000,000					1,100,000,000
Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Quarterly cash dividend (in dollars per share)							$ 0.52
Subsequent Event | Series A preferred stock
Equity, Class of Treasury Stock [Line Items]
Stock issued during the period, new issues (in shares)	99,264