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		4,179					4,179
Other comprehensive income (loss)		1,110						1,110
VE territory covered losses incurred		(8)				(8)
Recovery through conversion rate adjustment		1	$ (14)			15
Conversion to class A common stock upon sales into public market (in shares)			0	[2]	5
Conversion to class A common stock upon sales into public market		0	$ (329)		$ 329
Share-based compensation		177			$ 177
Stock issued under equity plans (in shares)					2
Stock issued under equity plans		56			$ 56
Restricted stock and performance-based shares settled in cash for taxes (in shares)	[2]				0
Restricted stock and performance-based shares settled in cash for taxes		(112)			$ (112)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(945)					(945)
Repurchase of class A common stock (in shares)					(16)
Repurchase of class A common stock		(3,115)			$ (168)		(2,947)
Ending balance (in shares) at Dec. 31, 2022			5
Balance as of end of period at Dec. 31, 2022		36,924	$ 1,981	[1]	$ 19,827	(28)	16,403	(1,259)
Ending balance (in shares) at Dec. 31, 2022					1,881
Beginning balance (in shares) at Sep. 30, 2023			5
Balance as of beginning of period at Sep. 30, 2023		38,733	$ 1,698	[3]	$ 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		4,890					4,890
Other comprehensive income (loss)		662						662
VE territory covered losses incurred		(24)				(24)
Recovery through conversion rate adjustment		0	$ (25)			25
Conversion to class A common stock upon sales into public market (in shares)			0	[4]	1
Conversion to class A common stock upon sales into public market		0	$ (58)		$ 58
Share-based compensation		209			$ 209
Stock issued under equity plans (in shares)					2
Stock issued under equity plans		104			$ 104
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		(172)			$ (172)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(1,060)					(1,060)
Repurchase of class A common stock (in shares)					(15)
Repurchase of class A common stock		(3,609)			$ (161)		(3,448)
Ending balance (in shares) at Dec. 31, 2023			5
Balance as of end of period at Dec. 31, 2023		$ 39,733	$ 1,615	[3]	$ 20,490	$ (139)	$ 18,422	$ (655)
Ending balance (in shares) at Dec. 31, 2023					1,836

[1] As of December 31, 2022 and September 30, 2022, the book value of series A preferred stock was $723 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 shares.

[3] As of December 31, 2023 and September 30, 2023, the book value of series A preferred stock was $398 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

[4] Increase or decrease is less than one million shares.