Financial Information by Segment - Financial Information by Reportable Segment (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Revenues from external customers	$ 965	$ 968
Reinforcement Materials [Member]
Segment Reporting Information [Line Items]
Revenues from external customers		22
Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Revenues from external customers		$ 4

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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+ Details