Litigation, Claims and Contingencies - Summary of Asbestos Claims Activity (Details) - Claim Claim in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Ashland [Member]
Asbestos claims [Roll Forward]
Open claims - beginning of year	46	49	53
New claims filed	2	2	2
Claims settled	(1)	(1)	(1)
Claims dismissed	(3)	(4)	(5)
Open claims - end of year	44	46	49
Hercules [Member]
Asbestos claims [Roll Forward]
Open claims - beginning of year	12	12	13
New claims filed	1	1	1
Claims dismissed	(2)	(1)	(2)
Open claims - end of year	11	12	12