Derivative Instruments and Hedging Activities - Derivative Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Derivatives, Fair Value [Line Items]
Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration]		Other current assets
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]		Other noncurrent assets
Derivative Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities	Other current liabilities
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other noncurrent liabilities	Other noncurrent liabilities
Foreign currency exchange derivatives
Derivatives, Fair Value [Line Items]
Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration]	Other current assets	Other current assets
Derivative asset, current	$ 15	$ 34
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets	Other noncurrent assets
Derivative asset, noncurrent	$ 3
Derivative Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities	Other current liabilities
Derivative liability, current	$ 32	$ 8
Derivative liability, noncurrent	9	6
Foreign currency exchange derivatives | Quoted Prices in Active Markets (Level 1)
Derivatives, Fair Value [Line Items]
Derivative asset, current	0	0
Derivative asset, noncurrent	0
Derivative liability, current	0	0
Derivative liability, noncurrent	0	0
Foreign currency exchange derivatives | Significant Other Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Derivative asset, current	15	34
Derivative asset, noncurrent	3
Derivative liability, current	32	8
Derivative liability, noncurrent	9	6
Foreign currency exchange derivatives | Significant Unobservable Inputs (Level 3)
Derivatives, Fair Value [Line Items]
Derivative asset, current	0	0
Derivative asset, noncurrent	0
Derivative liability, current	0	0
Derivative liability, noncurrent	0	0
Derivatives and Hedging Activities Designated as Hedging Instruments under ASC 815 | Foreign currency exchange derivatives
Derivatives, Fair Value [Line Items]
Derivative asset, current	9	30
Derivative asset, noncurrent	1	0
Total assets	10	30
Derivative liability, current	$ 32	$ 8
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other noncurrent liabilities	Other noncurrent liabilities
Total liabilities	$ 41	$ 144
Derivatives and Hedging Activities Designated as Hedging Instruments under ASC 815 | Foreign currency exchange derivatives | Other noncurrent liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, noncurrent	9	6
Derivatives and Hedging Activities Designated as Hedging Instruments under ASC 815 | Foreign currency exchange derivatives | Long-term debt
Derivatives, Fair Value [Line Items]
Derivative liability, noncurrent	0	130
Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815 | Foreign currency exchange derivatives
Derivatives, Fair Value [Line Items]
Derivative asset, current	6	4
Derivative asset, noncurrent	2	0
Total assets	8	4
Derivative liability, current	$ 0	$ 0
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other noncurrent liabilities	Other noncurrent liabilities
Total liabilities	$ 0	$ 0
Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815 | Foreign currency exchange derivatives | Other noncurrent liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, noncurrent	0	0
Derivatives and Hedging Activities Not Designated as Hedging Instruments under ASC 815 | Foreign currency exchange derivatives | Long-term debt
Derivatives, Fair Value [Line Items]
Derivative liability, noncurrent	$ 0	$ 0