Nonconsolidated Partially-Owned Affiliates - Income Statement (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Schedule of Equity Method Investments [Line Items]
Gross profit	$ 961	$ 928	$ 1,033
Equity method investment, nonconsolidated investee or group of investees
Schedule of Equity Method Investments [Line Items]
Net sales	3,513	3,783	3,791
Gross profit	306	368	346
Net income	138	184	173
Net income attributable to the entity	$ 136	$ 182	$ 171