Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Sales	$ 2,391	$ 2,111	$ 2,016
Life Sciences [Member]
Disaggregation Of Revenue [Line Items]
Sales	815	737	708
Life Sciences [Member] | North America [Member]
Disaggregation Of Revenue [Line Items]
Sales	244	229	226
Life Sciences [Member] | Europe [Member]
Disaggregation Of Revenue [Line Items]
Sales	267	242	229
Life Sciences [Member] | Asia Pacific [Member]
Disaggregation Of Revenue [Line Items]
Sales	218	192	181
Life Sciences [Member] | Latin America & Other [Member]
Disaggregation Of Revenue [Line Items]
Sales	86	74	72
Personal Care [Member]
Disaggregation Of Revenue [Line Items]
Sales	678	592	615
Personal Care [Member] | North America [Member]
Disaggregation Of Revenue [Line Items]
Sales	198	180	185
Personal Care [Member] | Europe [Member]
Disaggregation Of Revenue [Line Items]
Sales	270	240	258
Personal Care [Member] | Asia Pacific [Member]
Disaggregation Of Revenue [Line Items]
Sales	126	100	97
Personal Care [Member] | Latin America & Other [Member]
Disaggregation Of Revenue [Line Items]
Sales	84	72	75
Specialty Additives [Member]
Disaggregation Of Revenue [Line Items]
Sales	719	655	589
Specialty Additives [Member] | North America [Member]
Disaggregation Of Revenue [Line Items]
Sales	247	203	199
Specialty Additives [Member] | Europe [Member]
Disaggregation Of Revenue [Line Items]
Sales	258	246	218
Specialty Additives [Member] | Asia Pacific [Member]
Disaggregation Of Revenue [Line Items]
Sales	182	171	134
Specialty Additives [Member] | Latin America & Other [Member]
Disaggregation Of Revenue [Line Items]
Sales	32	35	38
Intermediates [Member]
Disaggregation Of Revenue [Line Items]
Sales	256	178	129
Intermediates [Member] | North America [Member]
Disaggregation Of Revenue [Line Items]
Sales	163	114	73
Intermediates [Member] | Europe [Member]
Disaggregation Of Revenue [Line Items]
Sales	39	28	24
Intermediates [Member] | Asia Pacific [Member]
Disaggregation Of Revenue [Line Items]
Sales	43	29	26
Intermediates [Member] | Latin America & Other [Member]
Disaggregation Of Revenue [Line Items]
Sales	$ 11	$ 7	$ 6