Goodwill and Other Intangible Assets (Schedule of Goodwill Balances) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Sep. 30, 2012
Goodwill And Other Intangible Asset [Line Items]
Balance at September 30, 2012	$ 480		$ 480
Measurement period adjustments	16	[1]
Foreign currency translation adjustment	(3)
Balance at March 31, 2013	493		480
Reinforcement Materials [Member]
Goodwill And Other Intangible Asset [Line Items]
Balance at September 30, 2012	28
Measurement period adjustments		[1]
Foreign currency translation adjustment	(2)
Balance at March 31, 2013	26
Performance Materials [Member]
Goodwill And Other Intangible Asset [Line Items]
Balance at September 30, 2012	11
Measurement period adjustments		[1]
Foreign currency translation adjustment
Balance at March 31, 2013	11
Advanced Technologies [Member]
Goodwill And Other Intangible Asset [Line Items]
Balance at September 30, 2012	2
Measurement period adjustments		[1]
Foreign currency translation adjustment
Balance at March 31, 2013	2
Purification Solutions [Member]
Goodwill And Other Intangible Asset [Line Items]
Balance at September 30, 2012	439
Measurement period adjustments	16	[1]
Foreign currency translation adjustment	(1)
Balance at March 31, 2013	$ 454

[1] Refer to Note C for further details related to the measurement period adjustments.