Financial Information by Segment - Financial Information by Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenues from external customers	$ 720	$ 611
Income (loss) from continuing operations before income taxes	92	75
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	692	580
Income (loss) from continuing operations before income taxes	113	95
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	28	31
Income (loss) from continuing operations before income taxes	(21)	(20)
Reinforcement Materials [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	387	295
Income (loss) from continuing operations before income taxes	62	40
Performance Chemicals [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	229	205
Income (loss) from continuing operations before income taxes	47	49
Purification Solutions [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	70	69
Income (loss) from continuing operations before income taxes	6	4
Specialty Fluids [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	6	11
Income (loss) from continuing operations before income taxes	$ (2)	$ 2

Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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