Goodwill and Other Intangibles - Summary of Goodwill by Reportable Segment (Parenthetical) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Sep. 30, 2021
Personal Care [Member]
Goodwill [Line Items]
Accumulated impairment	$ 356	$ 356
Specialty Additives [Member]
Goodwill [Line Items]
Accumulated impairment	174	174
Intermediates [Member]
Goodwill [Line Items]
Accumulated impairment	$ 90	$ 90

Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

Name:	us-gaap_GoodwillImpairedAccumulatedImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant