Litigation, Claims and Contingencies - Summary of Asbestos Claims Activity (Details) - Claim Claim in Thousands	6 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Ashland [Member]
Asbestos claims [Roll Forward]
Open claims - beginning of year	44	46	46	49	53
New claims filed	1	1	2	2	2
Claims settled	0	(1)	(1)	(1)	(1)
Claims dismissed	(2)	(1)	(3)	(4)	(5)
Open claims - end of period	43	45	44	46	49
Hercules [Member]
Asbestos claims [Roll Forward]
Open claims - beginning of year	11	12	12	12	13
New claims filed	1	1	1	1	1
Claims dismissed	0	(1)	(2)	(1)	(2)
Open claims - end of period	12	12	11	12	12