Reportable Segment Information - Summary of Financial Information for Each Reportable Segment (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2021
Segment Reporting Information [Line Items]
SALES		$ 644	$ 543	$ 1,759	$ 1,520
OPERATING INCOME (LOSS)		77	45	212	111
DEPRECIATION EXPENSE		37	40	111	115
AMORTIZATION EXPENSE		24	23	71	65
EBITDA	[1]	138	108	394	291
TOTAL ASSETS		6,412		6,412		$ 6,612
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
SALES	[2]	(23)	(15)	(57)	(29)
Life Sciences [Member]
Segment Reporting Information [Line Items]
SALES		228	193	602	548
OPERATING INCOME (LOSS)		51	37	115	101
DEPRECIATION EXPENSE		9	9	25	26
AMORTIZATION EXPENSE		7	7	21	21
EBITDA	[1]	67	53	161	148
TOTAL ASSETS		1,938		1,938		1,945
Personal Care [Member]
Segment Reporting Information [Line Items]
SALES		172	147	490	409
OPERATING INCOME (LOSS)		25	16	67	49
DEPRECIATION EXPENSE		10	10	28	29
AMORTIZATION EXPENSE		11	11	35	30
EBITDA	[1]	46	37	130	108
TOTAL ASSETS		1,087		1,087		1,145
Specialty Additives [Member]
Segment Reporting Information [Line Items]
SALES		194	169	532	474
OPERATING INCOME (LOSS)	[3]	35	15	79	36
DEPRECIATION EXPENSE		16	16	48	49
AMORTIZATION EXPENSE		5	5	14	14
EBITDA	[1]	56	36	141	99
TOTAL ASSETS		1,601		1,601		1,636
Intermediates [Member]
Segment Reporting Information [Line Items]
SALES		73	49	192	118
OPERATING INCOME (LOSS)		30	11	72	17
DEPRECIATION EXPENSE		2	4	9	10
AMORTIZATION EXPENSE		1	0	1	0
EBITDA	[1]	33	15	82	27
TOTAL ASSETS		185		185		160
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
OPERATING INCOME (LOSS)		(64)	(34)	(121)	(92)
DEPRECIATION EXPENSE		0	1	1	1
EBITDA	[1]	(64)	$ (33)	(120)	$ (91)
TOTAL ASSETS		$ 1,601		$ 1,601		$ 1,726

[1] Excludes income (loss) from discontinued operations, other net periodic benefit income (expense) and income (loss) on acquisitions and divestitures, net. See the Statement of Consolidated Comprehensive Income (Loss) for applicable amounts excluded.

[2] Intersegment sales from Intermediates are accounted for at prices that approximate fair value. All other intersegment transfers are accounted for at cost.

[3] Includes a capital project impairment of $9 million for the nine months ended June 30, 2021 relating to a long-term capital project plan change at a plant facility.