Derivative Instruments and Hedging Activities Disclosure - Gains (Losses) on Net Investment Hedges (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency translation adjustments	$ (91)	$ 305	$ 124
Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency translation adjustments	(155)	320	32
Currency Swap
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency translation adjustments	(70)	173	(21)
Terminated Currency Swap
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency translation adjustments	$ 13	$ 46	$ (35)