Income Taxes - Provisions for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Current expense (benefit):
Federal	$ 24	$ (48)	$ (85)
State	18	7	4
Foreign	50	85	70
Total current expense (benefit)	92	44	(11)
Deferred expense (benefit):
Federal	45	168	135
State	(17)	48	19
Foreign	193	262	(8)
Total deferred expense	221	478	146
Total income tax expense	$ 313	$ 522	$ 135