Financial Information by Segment - Revenue from External Customers by Geographic Region (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Net sales and other operating revenues	$ 968	$ 746
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	904	701
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	64	45
Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	323	243
Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	384	282
Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	197	176
Reinforcement Materials [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	541	375
Reinforcement Materials [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	206	149
Reinforcement Materials [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	240	155
Reinforcement Materials [Member] | Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	95	71
Performance Chemicals [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	302	267
Performance Chemicals [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	90	69
Performance Chemicals [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	136	118
Performance Chemicals [Member] | Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	76	80
Purification Solutions [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	61	59
Purification Solutions [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	27	25
Purification Solutions [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	8	9
Purification Solutions [Member] | Europe, Middle East and Africa [Member]
Segment Reporting Information [Line Items]
Net sales and other operating revenues	$ 26	$ 25