Derivative Instruments and Hedging Activities - Schedule of Effective Portion of Pretax Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Total	$ (10)	$ 1	$ 0	$ 13
Foreign currency exchange derivatives | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gain (loss) on foreign currency exchange derivatives not designated as hedging instrument	(2)	8	(1)	11
Foreign currency exchange derivatives | Net financing charges
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax gain (loss) on foreign currency exchange derivatives not designated as hedging instrument	(8)	(7)	1	2
Foreign currency exchange derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency exchange derivatives	12	33	38	65
Foreign currency exchange derivatives | Cash Flow Hedging | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion of pretax gain (loss) reclassified from AOCI into income	18	15	33	22
Foreign currency exchange derivatives | Cash Flow Hedging | Net financing charges
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion of pretax gain (loss) reclassified from AOCI into income	$ (3)	$ 0	$ 3	$ 0