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Reportable Segment Information - Summary of Financial Information for Each Reportable Segment (Parenthetical) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Mar. 31, 2025 | Mar. 31, 2024
Segment Reporting Information [Line Items] |  |  |  |
Income (loss) on acquisitions and divestitures | $ 18 | $ 0 | $ (165) | $ (2)
Avoca [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Income (loss) on acquisitions and divestitures | 8 |  | 8 |
Impairment charge |  |  | 183 |
Life Sciences [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Accelerated depreciation | $ 13 |  | $ 13 |
Specialty Additives [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Accelerated depreciation |  | $ 27 |  | $ 49

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