Fair Value Measurements - Schedule of Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investment with readily determinable fair value	$ 8	$ 9
Derivative asset, statement of financial position [extensible enumeration]		Other assets
(Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investment with readily determinable fair value	8	$ 9
(Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investment with readily determinable fair value	0	0
(Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investment with readily determinable fair value	0	$ 0
Foreign Exchange Contract | Other Current Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other current liabilities	(3)
Foreign Exchange Contract | Other Current Liabilities | (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other current liabilities	0
Foreign Exchange Contract | Other Current Liabilities | (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other current liabilities	(3)
Foreign Exchange Contract | Other Current Liabilities | (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other current liabilities	$ 0