Income Taxes - Income Tax Expense by Fiscal Year (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Current:
U.S. federal	$ 2,694	$ 2,630	$ 2,166
State and local	298	293	104
Non-U.S.	1,281	1,324	1,245
Total current taxes	4,273	4,247	3,515
Deferred:
U.S. federal	(132)	(339)	(231)
State and local	(18)	(1)	(77)
Non-U.S.	50	(143)	(28)
Total deferred taxes	(100)	(483)	(336)
Total income tax provision	$ 4,173	$ 3,764	$ 3,179