Derivative Instruments and Hedging Activities Disclosure - Gains (Losses) on Net Investment Hedges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Foreign Currency-Denominated Debt
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), before Reclassification and Tax	$ (56)	$ 39	$ (46)	$ 81
Currency Swap
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), before Reclassification and Tax	(122)	(14)	19	(14)
Foreign Exchange Forward
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), before Reclassification and Tax	$ 0	$ (9)	$ 0	$ (9)