Debt - Summary of Net Interest and Other Expense (Income) (Details) - USD ($) $ in Millions		12 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Debt Disclosure [Abstract]
Interest expense	[1]	$ 53	$ 54	$ 62
Interest income		(10)	(12)	(4)
Loss on the accounts receivables sale programs		6	3	1
Investment securities income	[2]	(75)	(42)	86
Other financing costs		2	3	4
Interest Income (Expense), Net		$ (24)	$ 6	$ 149

[1] Includes $1 million of accelerated accretion and/or amortization for original issue discounts and debt issuance costs during 2022.

[2] Represents investment loss (income) related to the restricted investments discussed in Note E.