Equity - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance			$ 17,402
Other comprehensive income	$ (69)	$ (378)	33	$ (293)
Ending Balance	17,463	17,143	17,463	17,143
AOCI Attributable to Parent
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(846)	(345)	(911)	(434)
Ending Balance	(870)	(662)	(870)	(662)
Foreign currency translation adjustments
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(843)	(343)	(901)	(421)
Other comprehensive income	(25)	(298)	33	(220)
Other comprehensive income, tax effect	0	0	0	0
Ending Balance	(868)	(641)	(868)	(641)
Realized and unrealized gains (losses) on derivatives
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(3)	(4)	(11)	(17)
Other comprehensive income, before reclassifications	(1)	(13)	3	3
Reclassification to income	3	(6)	7	(9)
Other comprehensive income, tax effect	0	(4)	1	2
Reclassification to income, tax effect	1	(3)	1	(5)
Ending Balance	(1)	(23)	(1)	(23)
Pension and postretirement plans
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	0	2	1	4
Reclassification to income	(1)	0	(2)	(2)
Reclassification to income, tax effect	0	0	(1)	(1)
Ending Balance	$ (1)	$ 2	$ (1)	$ 2