Restructuring Activities - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Restructuring Cost And Reserve [Line Items]
Severance income (expenses)	$ (4)	$ (3)	$ (13)	$ (23)
Specialty Additives Facility [Member]
Restructuring Cost And Reserve [Line Items]
Accelerated depreciation		7		55
Life Sciences [Member]
Restructuring Cost And Reserve [Line Items]
Accelerated depreciation	8		21
Specialty Additives [Member]
Restructuring Cost And Reserve [Line Items]
Accelerated depreciation	19	7	19	55
Fiscal 2025 and 2023 Restructuring Severance Costs [Member] \| Life Sciences [Member]
Restructuring Cost And Reserve [Line Items]
Accelerated depreciation	27		40
Fiscal 2025 and 2023 Restructuring Severance Costs [Member] \| Personal Care [Member]
Restructuring Cost And Reserve [Line Items]
Accelerated depreciation	27	$ 1	40	$ 1
Fiscal 2025 and 2023 Restructuring Severance Costs [Member] \| Specialty Additives [Member]
Restructuring Cost And Reserve [Line Items]
Accelerated depreciation	$ 27		$ 40

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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