CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) shares in Millions, $ in Millions		Total	Cumulative Effect, Period of Adoption, Adjustment	Series A convertible participating preferred stock	Preferred Stock		Preferred Stock Series A convertible participating preferred stock		Common Stock and Additional Paid-in Capital	Right to Recover for Covered Losses	Accumulated Income	Accumulated Income Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Income (Loss), Net	Accumulated Other Comprehensive Income (Loss), Net Cumulative Effect, Period of Adoption, Adjustment
Beginning Balance (in shares) at Sep. 30, 2019					5
Beginning Balance at Sep. 30, 2019		$ 34,684	$ 0		$ 5,462				$ 16,541	$ (171)	$ 13,502	$ 25	$ (650)	$ (25)
Beginning Balance (in shares) at Sep. 30, 2019									1,974
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		10,866									10,866
Other comprehensive income (loss), net of tax		1,029											1,029
VE territory covered losses incurred		(37)								(37)
Recovery through conversion rate adjustment		5			$ (164)					169
Issuance of stock (in shares)							0	[1]	4
Issuance of stock		190		$ (5)			$ (5)		$ 190
Conversion to class A common stock upon sales into public market (in shares)					0	[1]			6
Conversion to class A common stock upon sales into public market		0			$ (207)				$ 207
Share-based compensation, net of forfeitures		416							$ 416
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		$ (160)							$ (160)
Dividends declared, quarterly, per share (in dollars per share)		$ 0.30
Cash dividends declared and paid, at a quarterly amount per Class A share		$ (2,664)									(2,664)
Repurchase of class A common stock (in shares)									(44)
Repurchase of class A common stock		(8,114)							$ (473)		(7,641)
Ending Balance (in shares) at Sep. 30, 2020					5
Ending Balance (in shares) at Sep. 30, 2020									1,939
Ending Balance at Sep. 30, 2020		36,210	$ 3		$ 5,086	[2]			$ 16,721	(39)	14,088	$ 3	354
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		12,311									12,311
Other comprehensive income (loss), net of tax		82											82
VE territory covered losses incurred		(147)								(147)
Recovery through conversion rate adjustment		(2)			$ (55)					53
Issuance of stock (in shares)									5
Issuance of stock		208							$ 208
Conversion to class A common stock upon sales into public market (in shares)					0	[3]			29
Conversion to class A common stock upon sales into public market		0			$ (1,951)				$ 1,951
Share-based compensation, net of forfeitures		542							$ 542
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		$ (144)							$ (144)
Dividends declared, quarterly, per share (in dollars per share)		$ 0.32
Cash dividends declared and paid, at a quarterly amount per Class A share		$ (2,798)									(2,798)
Repurchase of class A common stock (in shares)									(40)
Repurchase of class A common stock		(8,676)							$ (423)		(8,253)
Ending Balance (in shares) at Sep. 30, 2021				0	5
Ending Balance (in shares) at Sep. 30, 2021									1,932
Ending Balance at Sep. 30, 2021		37,589			$ 3,080	[2],[4]			$ 18,855	(133)	15,351		436
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		14,957									14,957
Other comprehensive income (loss), net of tax		(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	[5]	4
Issuance of stock		196		$ (3)			$ (3)		$ 196
Conversion to class A common stock upon sales into public market (in shares)					0	[5]			10
Conversion to class A common stock upon sales into public market		0			$ (612)				$ 612
Share-based compensation, net of forfeitures		602							$ 602
Restricted stock and performance-based shares settled in cash for taxes (in shares)	[5]								0
Restricted stock and performance-based shares settled in cash for taxes		$ (120)							$ (120)
Dividends declared, quarterly, per share (in dollars per share)		$ 0.375
Cash dividends declared and paid, at a quarterly amount per Class A share		$ (3,203)									(3,203)
Repurchase of class A common stock (in shares)									(56)
Repurchase of class A common stock		(11,589)							$ (600)		(10,989)
Ending Balance (in shares) at Sep. 30, 2022				0	5
Ending Balance (in shares) at Sep. 30, 2022									1,890
Ending Balance at Sep. 30, 2022		$ 35,581			$ 2,324	[4]			$ 19,545	$ (35)	$ 16,116		$ (2,369)

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

[2] As of September 30, 2021 and 2020, the book value of series A preferred stock was $486 million and $2.4 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.

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

[4] 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 series C preferred stock.

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