Derivative Instruments and Hedging Activities - Location and Fair Values of Derivative Instruments and Hedging Activities (Details) - USD ($) $ in Millions	Mar. 31, 2023	Sep. 30, 2022
Derivative [Line Items]
Total assets	$ 36	$ 54
Total liabilities	3,455	3,138
Derivatives and Hedging Activities  Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total assets	31	30
Total liabilities	3,443	3,111
Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total assets	5	24
Total liabilities	12	27
Other current assets | Foreign currency exchange derivatives | Derivatives and Hedging Activities  Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total assets	23	30
Other current assets | Foreign currency exchange derivatives | Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total assets	5	24
Other current assets | Interest rate swaps | Derivatives and Hedging Activities  Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total assets	5	0
Other current assets | Interest rate swaps | Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total assets	0	0
Other current assets | Commodity derivatives | Derivatives and Hedging Activities  Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total assets	3	0
Other current assets | Commodity derivatives | Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total assets	0	0
Other current liabilities | Foreign currency exchange derivatives | Derivatives and Hedging Activities  Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total liabilities	36	24
Other current liabilities | Foreign currency exchange derivatives | Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total liabilities	12	27
Other current liabilities | Commodity derivatives | Derivatives and Hedging Activities  Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total liabilities	1	10
Other current liabilities | Commodity derivatives | Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total liabilities	0	0
Long-term debt | Foreign currency denominated debt | Derivatives and Hedging Activities  Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total liabilities	3,406	3,077
Long-term debt | Foreign currency denominated debt | Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815
Derivative [Line Items]
Total liabilities	$ 0	$ 0