Financial Information by Segment & Geographic Area (Financial Information by Segment) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended										12 Months Ended
	Sep. 30, 2012		Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011		Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2010
Segment Reporting Information [Line Items]
Revenues from external customers	$ 848		$ 846	$ 844	$ 762	$ 833		$ 836	$ 739	$ 694	$ 3,300	[1]	$ 3,102	[1]	$ 2,716	[1]
Depreciation and amortization											156		139		137
Equity in earnings of affiliated companies	3		4	3	1	2		2	1	3	11		8		7
Income (loss) from continuing operations before taxes											245	[2]	203	[2]	166	[2]
Assets	4,399	[3]				3,141	[3]				4,399	[3]	3,141	[3]	2,886	[3]
Total expenditures for additions to long-lived assets											622		241	[4]	107	[4]
Reinforcement Materials [Member]
Segment Reporting Information [Line Items]
Revenues from external customers											2,019	[1]	1,952	[1]	1,660	[1]
Depreciation and amortization											82		80		74
Equity in earnings of affiliated companies											9		7		6
Income (loss) from continuing operations before taxes											227	[2]	183	[2]	139	[2]
Assets	1,527	[3]				1,509	[3]				1,527	[3]	1,509	[3]	1,277	[3]
Total expenditures for additions to long-lived assets											163		126	[4]	62	[4]
Performance Materials [Member]
Segment Reporting Information [Line Items]
Revenues from external customers											914	[1]	880	[1]	783	[1]
Depreciation and amortization											47		37		35
Equity in earnings of affiliated companies											1		1		1
Income (loss) from continuing operations before taxes											128	[2]	140	[2]	125	[2]
Assets	717	[3]				661	[3]				717	[3]	661	[3]	544	[3]
Total expenditures for additions to long-lived assets											87		99	[4]	38	[4]
Advanced Technologies [Member]
Segment Reporting Information [Line Items]
Revenues from external customers											210	[1]	186	[1]	186	[1]
Depreciation and amortization											13		14		12
Income (loss) from continuing operations before taxes											49	[2]	31	[2]	50	[2]
Assets	209	[3]				191	[3]				209	[3]	191	[3]	188	[3]
Total expenditures for additions to long-lived assets											16		10	[4]	4	[4]
Purification Solutions [Member]
Segment Reporting Information [Line Items]
Revenues from external customers											61	[1]
Depreciation and amortization											8
Equity in earnings of affiliated companies											1
Income (loss) from continuing operations before taxes											5	[2]
Assets	1,433	[3]									1,433	[3]
Total expenditures for additions to long-lived assets											350
Segment Total [Member]
Segment Reporting Information [Line Items]
Revenues from external customers											3,204	[1]	3,018	[1]	2,629	[1]
Depreciation and amortization											150		131		121
Equity in earnings of affiliated companies											11		8		7
Income (loss) from continuing operations before taxes											409	[2]	354	[2]	314	[2]
Assets	3,886	[3]				2,361	[3]				3,886	[3]	2,361	[3]	2,009	[3]
Total expenditures for additions to long-lived assets											616		235	[4]	104	[4]
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Revenues from external customers											96	[1],[2],[5]	84	[1],[2],[5]	87	[1],[2],[5]
Depreciation and amortization											6	[2],[5]	8	[2],[5]	16	[2],[5]
Income (loss) from continuing operations before taxes											(164)	[2],[5]	(151)	[2],[5]	(148)	[2],[5]
Assets	513	[2],[3],[5]				780	[2],[3],[5]				513	[2],[3],[5]	780	[2],[3],[5]	877	[2],[3],[5]
Total expenditures for additions to long-lived assets											$ 6	[2],[5]	$ 6	[2],[4],[5]	$ 3	[2],[4],[5]

[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 for Unallocated and Other includes:

[3] Unallocated and Other assets includes cash, marketable securities, cost investments, income taxes receivable, deferred taxes, headquarters' assets, and current and non-current assets held for sale.

[4] Expenditures for additions to long-lived assets include total equity and other investments (including available-for-sale securities), property, plant and equipment, intangible assets and assets held for rent.

[5] Unallocated and other includes certain items and eliminations necessary to reflect management's reporting of operating segment results. These items are reflective of the segment reporting presented to the Chief Operating Decision Maker.