Income Taxes - Summary of Provision for Income Taxes Related to Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Current
Federal	$ 21	$ (17)	$ 3
State	3	(5)	7
Foreign	55	46	50
Total current income tax expense (benefit)	79	24	60
Deferred	(302)	(32)	(35)
Income tax expense (benefit)	$ (223)	$ (8)	$ 25