Financial Information by Segment (Financial Information by Reportable Segment) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Segment Reporting Information [Line Items]
Revenues from external customers	$ 903	[1]	$ 846	[1]	$ 2,565	[1]	$ 2,452	[1]
Income (loss) before taxes	73	[2]	78	[2]	150	[2]	209	[2]
Reinforcement Materials [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	486	[1]	517	[1]	1,420	[1]	1,540	[1]
Income (loss) before taxes	48	[2]	59	[2]	139	[2]	186	[2]
Performance Materials [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	233	[1]	247	[1]	672	[1]	687	[1]
Income (loss) before taxes	35	[2]	38	[2]	98	[2]	94	[2]
Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	69	[1]	57	[1]	148	[1]	153	[1]
Income (loss) before taxes	27	[2]	12	[2]	42	[2]	33	[2]
Purification Solutions [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	86	[1]			258	[1]
Income (loss) before taxes	1	[2]			11	[2]
Segment Total [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	874	[1]	821	[1]	2,498	[1]	2,380	[1]
Income (loss) before taxes	111	[2]	109	[2]	290	[2]	313	[2]
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers	29	[1]	25	[1]	67	[1]	72	[1]
Income (loss) before taxes	$ (38)	[2]	$ (31)	[2]	$ (140)	[2]	$ (104)	[2]

[1] Unallocated and other reflects royalties paid by equity affiliates, external shipping and handling fees, and the impact of the corporate adjustment for unearned revenue.

[2] Income (loss) from continuing operations before taxes that are categorized as Unallocated and Other includes: