Income Taxes - Income Before Taxes by Fiscal Year (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
U.S.	$ 14,537	$ 13,339	$ 11,051
Non-U.S.	9,379	7,698	7,085
Income before income taxes	$ 23,916	$ 21,037	$ 18,136