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, 2023			5
Balance as of beginning of period at Sep. 30, 2023		$ 38,733	$ 1,698	[1]	$ 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		9,553					9,553
Other comprehensive income (loss)		319						319
VE territory covered losses		(60)				(60)
Recovery through conversion rate adjustment		0	$ (25)			25
Conversions to class A common stock (in shares)			0	[2]	2
Conversions to class A common stock		0	$ (71)		$ 71
Share-based compensation		451			$ 451
Stock issued under equity plans (in shares)					3
Stock issued under equity plans		183			$ 183
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		(181)			$ (181)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(2,120)					(2,120)
Repurchases of class A common stock (in shares)					(25)
Repurchases of class A common stock		(6,393)			$ (267)		(6,126)
Ending balance (in shares) at Mar. 31, 2024			5
Balance as of end of period at Mar. 31, 2024		40,485	$ 1,602	[1]	$ 20,709	(175)	19,347	(998)
Ending balance (in shares) at Mar. 31, 2024					1,828
Beginning balance (in shares) at Dec. 31, 2023			5
Balance as of beginning of period at Dec. 31, 2023		39,733	$ 1,615		$ 20,490	(139)	18,422	(655)
Beginning balance (in shares) at Dec. 31, 2023					1,836
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		4,663					4,663
Other comprehensive income (loss)		(343)						(343)
VE territory covered losses		(36)				(36)
Conversions to class A common stock (in shares)			0	[3]	1
Conversions to class A common stock		0	$ (13)		$ 13
Share-based compensation		242			$ 242
Stock issued under equity plans (in shares)					1
Stock issued under equity plans		79			$ 79
Shares withheld for taxes related to stock issued under equity plans (in shares)	[3]				0
Shares withheld for taxes related to stock issued under equity plans		(9)			$ (9)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(1,060)					(1,060)
Repurchases of class A common stock (in shares)					(10)
Repurchases of class A common stock		(2,784)			$ (106)		(2,678)
Ending balance (in shares) at Mar. 31, 2024			5
Balance as of end of period at Mar. 31, 2024		$ 40,485	$ 1,602	[1]	$ 20,709	(175)	19,347	(998)
Ending balance (in shares) at Mar. 31, 2024					1,828
Beginning balance (in shares) at Sep. 30, 2024		5	5
Balance as of beginning of period at Sep. 30, 2024		$ 39,137	$ 1,031	[4]	$ 21,229	(104)	17,289	(308)
Beginning balance (in shares) at Sep. 30, 2024					1,868
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		9,696					9,696
Other comprehensive income (loss)		(519)						(519)
VE territory covered losses		(24)				(24)
Recovery through conversion rate adjustment		0	$ (8)			8
Conversions to class A common stock (in shares)			0	[5]	4
Conversions to class A common stock		0	$ (143)		$ 143
Share-based compensation		483			$ 483
Stock issued under equity plans (in shares)					4
Stock issued under equity plans		246			$ 246
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		(242)			$ (242)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(2,334)					(2,334)
Repurchases of class A common stock (in shares)					(26)
Repurchases of class A common stock		$ (8,413)			$ (280)		(8,133)
Ending balance (in shares) at Mar. 31, 2025		5	5
Balance as of end of period at Mar. 31, 2025		$ 38,030	$ 880	[4]	$ 21,579	(120)	16,518	(827)
Ending balance (in shares) at Mar. 31, 2025					1,849
Beginning balance (in shares) at Dec. 31, 2024			5
Balance as of beginning of period at Dec. 31, 2024		38,296	$ 904		$ 21,324	(123)	17,438	(1,247)
Beginning balance (in shares) at Dec. 31, 2024					1,860
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		4,577					4,577
Other comprehensive income (loss)		420						420
VE territory covered losses		3				3
Conversions to class A common stock (in shares)			0	[6]	1
Conversions to class A common stock		0	$ (24)		$ 24
Share-based compensation		259			$ 259
Stock issued under equity plans (in shares)					1
Stock issued under equity plans		119			$ 119
Shares withheld for taxes related to stock issued under equity plans (in shares)	[6]				0
Shares withheld for taxes related to stock issued under equity plans		(7)			$ (7)
Cash dividends declared and paid, at a quarterly amount per class A common stock		(1,164)					(1,164)
Repurchases of class A common stock (in shares)					(13)
Repurchases of class A common stock		$ (4,473)			$ (140)		(4,333)
Ending balance (in shares) at Mar. 31, 2025		5	5
Balance as of end of period at Mar. 31, 2025		$ 38,030	$ 880	[4]	$ 21,579	$ (120)	$ 16,518	$ (827)
Ending balance (in shares) at Mar. 31, 2025					1,849

[1] As of March 31, 2024 and September 30, 2023, the book value of series A preferred stock was $385 million and $456 million, respectively. See 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 March 31, 2025 and September 30, 2024, the book value of series A convertible participating preferred stock (series A preferred stock) was $397 million and $540 million, respectively. See 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).

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

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