Goodwill and Intangible Assets (Tables)

6 Months Ended

Mar. 31, 2025

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in Balances

The carrying amount of goodwill attributable to each reportable segment and the changes in those balances during the six months ended March 31, 2025 are as follows:

	Reinforcement Materials			Performance Chemicals			Total
	(In millions)
Balance at September 30, 2024	$	48		$	85		$	133
Foreign currency impact		(2	)		(3	)		(5	)
Balance at March 31, 2025	$	46		$	82		$	128

Schedule of Intangible Assets

The following table provides information regarding the Company’s intangible assets:

	March 31, 2025							September 30, 2024
	Gross Carrying Value		Accumulated Amortization			Net Intangible Assets		Gross Carrying Value		Accumulated Amortization			Net Intangible Assets
	(In millions)
Intangible assets with finite lives
Developed technologies(1)	$	40	$	(13	)	$	27	$	34	$	(12	)	$	22
Trademarks		2		(1	)	$	1		2		(1	)		1
Customer relationships		58		(31	)	$	27		60		(30	)		30
Total intangible assets	$	100	$	(45	)	$	55	$	96	$	(43	)	$	53

(1)Included within Developed technologies as of March 31, 2025 is $8 million of intangible assets acquired during the first quarter of fiscal 2025 as discussed in Note C above.