Income Taxes - Schedule of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Current
Federal	$ 36	$ 16	$ 10
State	14	11	5
Non-U.S.	25	15	19
Current income tax expense	75	42	34
Deferred
Federal	42	62	24
State	8	26	0
Non-U.S.	(2)	4	(1)
Deferred income tax expense	48	92	23
Income tax expense	$ 123	$ 134	$ 57