CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) shares in Millions, $ in Millions		Total	Series A preferred stock	Preferred Stock		Preferred Stock Series A preferred stock		Common Stock and Additional Paid-in Capital		Common Stock and Additional Paid-in Capital Series A preferred stock	Right to Recover for Covered Losses	Accumulated Income	Accumulated Other Comprehensive Income (Loss)
Beginning Balance (in shares) at Sep. 30, 2021				5
Balance as of beginning of period at Sep. 30, 2021		$ 37,589		$ 3,080	[1]			$ 18,855			$ (133)	$ 15,351	$ 436
Beginning Balance (in shares) at Sep. 30, 2021								1,932
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		14,957										14,957
Other comprehensive income (loss)		(2,805)											(2,805)
VE territory covered losses incurred		(43)									(43)
Recovery through conversion rate adjustment		0		$ (141)							141
Issuance of stock (in shares)						0	[2]	4
Issuance of stock		196	$ (3)			$ (3)		$ 196
Conversions to class A common stock (in shares)				0	[2]			10
Conversions to class A common stock		0		$ (612)				$ 612
Share-based compensation		602						$ 602
Shares withheld for taxes related to stock issued under equity plans (in shares)	[2]							0
Shares withheld for taxes related to stock issued under equity plans		(120)						$ (120)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(3,203)										(3,203)
Repurchases of class A common stock (in shares)								(56)
Repurchases of class A common stock		(11,589)						$ (600)				(10,989)
Ending Balance (in shares) at Sep. 30, 2022				5
Balance as of end of period at Sep. 30, 2022		35,581		$ 2,324	[1],[3]			$ 19,545			(35)	16,116	(2,369)
Ending Balance (in shares) at Sep. 30, 2022								1,890
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		17,273										17,273
Other comprehensive income (loss)		1,052											1,052
VE territory covered losses incurred		(136)									(136)
Recovery through conversion rate adjustment		1		$ (30)							31
Issuance of stock (in shares)								5
Issuance of stock		260						$ 260
Conversions to class A common stock (in shares)				0	[4]			10
Conversions to class A common stock		0		$ (596)				$ 596
Share-based compensation		765						$ 765
Shares withheld for taxes related to stock issued under equity plans (in shares)								(1)
Shares withheld for taxes related to stock issued under equity plans		(130)						$ (130)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(3,751)										(3,751)
Repurchases of class A common stock (in shares)								(55)
Repurchases of class A common stock		$ (12,182)						$ (584)				(11,598)
Ending Balance (in shares) at Sep. 30, 2023		5	0	5
Balance as of end of period at Sep. 30, 2023		$ 38,733		$ 1,698	[3],[5]			$ 20,452			(140)	18,040	(1,317)
Ending Balance (in shares) at Sep. 30, 2023								1,849
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		19,743										19,743
Other comprehensive income (loss)		1,009											1,009
VE territory covered losses incurred		(139)									(139)
Recovery through conversion rate adjustment		(6)		$ (181)							175
Issuance of stock (in shares)						0	[6]	6
Issuance of stock		335	$ (5)			$ (5)	[6]	$ 335
Conversions to class A common stock (in shares)				0	[6]			151
Conversions to class A common stock		0		$ (481)				$ 481
Class B-1 common stock exchange offer (in shares)								(73)
Class B-1 common stock exchange offer		0						$ 0	[6]
Share-based compensation		850						$ 850
Shares withheld for taxes related to stock issued under equity plans (in shares)								(1)
Shares withheld for taxes related to stock issued under equity plans		(208)						$ (208)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(4,217)										(4,217)
Repurchases of class A common stock (in shares)								(64)
Repurchases of class A common stock		$ (16,958)						$ (681)				(16,277)
Ending Balance (in shares) at Sep. 30, 2024		5	0	5
Balance as of end of period at Sep. 30, 2024		$ 39,137		$ 1,031	[5]			$ 21,229			$ (104)	$ 17,289	$ (308)
Ending Balance (in shares) at Sep. 30, 2024								1,868

[1] As of September 30, 2022 and 2021, the book value of series A preferred stock was $1.0 billion and $486 million, respectively. Refer to Note 5—U.S. and Europe Retrospective Responsibility Plans for the book value of series B and C preferred stock.

[2] Increase or decrease is less than one million

[3] As of September 30, 2023 and 2022, the book value of series A preferred stock was $456 million and $1.0 billion, respectively. Refer to Note 5—U.S. and Europe Retrospective Responsibility Plans for the book value of series B and C preferred stock.

[4] Increase or decrease is less than one million

[5] As of September 30, 2024 and 2023, the book value of series A convertible participating preferred stock (series A preferred stock) was $540 million and $456 million, respectively. Refer to Note 5—U.S. and Europe Retrospective Responsibility Plans for the book value of series B convertible participating preferred stock (series B preferred stock) and series C convertible participating preferred stock (series C preferred stock).

[6] Increase or decrease is less than one million.