CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (UNAUDITED) - USD ($) shares in Millions, $ in Millions		Total	Preferred Stock		Common Stock and Additional Paid-in Capital		Right to Recover for Covered Losses	Accumulated Income	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Sep. 30, 2022			5
Balance as of beginning of period at Sep. 30, 2022		$ 35,581	$ 2,324	[1]	$ 19,545		$ (35)	$ 16,116	$ (2,369)
Beginning balance (in shares) at Sep. 30, 2022					1,890
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		12,592						12,592
Other comprehensive income (loss)		1,391							1,391
VE territory covered losses incurred		(21)					(21)
Recovery through conversion rate adjustment		1	$ (30)				31
Conversions to class A common stock (in shares)			0	[2]	8
Conversions to class A common stock		0	$ (508)		$ 508
Share-based compensation		591			$ 591
Stock issued under equity plans (in shares)					4
Stock issued under equity plans		189			$ 189
Restricted stock and performance-based shares settled in cash for taxes (in shares)					(1)
Restricted stock and performance-based shares settled in cash for taxes		(125)			$ (125)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(2,823)						(2,823)
Repurchases of class A common stock (in shares)					(39)
Repurchases of class A common stock		(8,395)			$ (418)			(7,977)
Ending balance (in shares) at Jun. 30, 2023			5
Balance as of end of period at Jun. 30, 2023		38,981	$ 1,786	[1]	$ 20,290		(25)	17,908	(978)
Ending balance (in shares) at Jun. 30, 2023					1,862
Beginning balance (in shares) at Mar. 31, 2023			5
Balance as of beginning of period at Mar. 31, 2023		38,565	$ 1,885		$ 20,095		(35)	17,610	(990)
Beginning balance (in shares) at Mar. 31, 2023					1,874
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		4,156						4,156
Other comprehensive income (loss)		12							12
VE territory covered losses incurred		(6)					(6)
Recovery through conversion rate adjustment		0	$ (16)				16
Conversions to class A common stock (in shares)			0	[3]	1
Conversions to class A common stock		0	$ (83)		$ 83
Share-based compensation		191			$ 191
Stock issued under equity plans (in shares)					1
Stock issued under equity plans		71			$ 71
Restricted stock and performance-based shares settled in cash for taxes (in shares)					(1)
Restricted stock and performance-based shares settled in cash for taxes		(7)			$ (7)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(937)						(937)
Repurchases of class A common stock (in shares)					(13)
Repurchases of class A common stock		(3,064)			$ (143)			(2,921)
Ending balance (in shares) at Jun. 30, 2023			5
Balance as of end of period at Jun. 30, 2023		$ 38,981	$ 1,786	[1]	$ 20,290		(25)	17,908	(978)
Ending balance (in shares) at Jun. 30, 2023					1,862
Beginning balance (in shares) at Sep. 30, 2023		5	5
Balance as of beginning of period at Sep. 30, 2023		$ 38,733	$ 1,698	[4]	$ 20,452		(140)	18,040	(1,317)
Beginning balance (in shares) at Sep. 30, 2023					1,849
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		14,425						14,425
Other comprehensive income (loss)		257							257
VE territory covered losses incurred		(81)					(81)
Recovery through conversion rate adjustment		(6)	$ (181)				175
Conversions to class A common stock (in shares)			0	[5]	93
Conversions to class A common stock		0	$ (92)		$ 92
Class B-1 common stock exchange offer (in shares)					(73)
Class B-1 common stock exchange offer		0			$ 0	[5]
Share-based compensation		662			$ 662
Stock issued under equity plans (in shares)					4
Stock issued under equity plans		267			$ 267
Restricted stock and performance-based shares settled in cash for taxes (in shares)					(1)
Restricted stock and performance-based shares settled in cash for taxes		(189)			$ (189)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(3,176)						(3,176)
Repurchases of class A common stock (in shares)					(42)
Repurchases of class A common stock		$ (11,163)			$ (452)			(10,711)
Ending balance (in shares) at Jun. 30, 2024		5	5
Balance as of end of period at Jun. 30, 2024		$ 39,729	$ 1,425	[4]	$ 20,832		(46)	18,578	(1,060)
Ending balance (in shares) at Jun. 30, 2024					1,830
Beginning balance (in shares) at Mar. 31, 2024			5
Balance as of beginning of period at Mar. 31, 2024		40,485	$ 1,602		$ 20,709		(175)	19,347	(998)
Beginning balance (in shares) at Mar. 31, 2024					1,828
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		4,872						4,872
Other comprehensive income (loss)		(62)							(62)
VE territory covered losses incurred		(21)					(21)
Recovery through conversion rate adjustment		(6)	$ (156)				150
Conversions to class A common stock (in shares)			0	[6]	91
Conversions to class A common stock		0	$ (21)		$ 21
Class B-1 common stock exchange offer (in shares)					(73)
Class B-1 common stock exchange offer		0			$ 0	[6]
Share-based compensation		211			$ 211
Stock issued under equity plans (in shares)					1
Stock issued under equity plans		84			$ 84
Restricted stock and performance-based shares settled in cash for taxes (in shares)	[6]				0
Restricted stock and performance-based shares settled in cash for taxes		(8)			$ (8)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(1,056)						(1,056)
Repurchases of class A common stock (in shares)					(17)
Repurchases of class A common stock		$ (4,770)			$ (185)			(4,585)
Ending balance (in shares) at Jun. 30, 2024		5	5
Balance as of end of period at Jun. 30, 2024		$ 39,729	$ 1,425	[4]	$ 20,832		$ (46)	$ 18,578	$ (1,060)
Ending balance (in shares) at Jun. 30, 2024					1,830

[1] As of June 30, 2023 and September 30, 2022, the book value of series A preferred stock was $544 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 series C preferred stock.

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

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

[4] As of June 30, 2024 and September 30, 2023, the book value of series A preferred stock was $364 million and $456 million, respectively. Refer to Note 5—U.S. and Europe Retrospective Responsibility Plans for the book value of series B and series C preferred stock

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

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