Goodwill and Other Intangible Assets (Schedule of Goodwill Balances) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended						9 Months Ended
	Jun. 30, 2013		Jun. 30, 2013 Reinforcement Materials [Member]	Jun. 30, 2013 Performance Materials [Member]	Jun. 30, 2013 Advanced Technologies [Member]	Sep. 30, 2012 Advanced Technologies [Member]	Jun. 30, 2013 Purification Solutions [Member]
Goodwill And Other Intangible Asset [Line Items]
Balance at September 30, 2012	$ 480		$ 28	$ 11	$ 2	$ 2	$ 439
Measurement period adjustments	22	[1]					22	[1]
Foreign currency translation adjustment	(3)		(3)	(1)			1
Balance at June 30, 2013	$ 499		$ 25	$ 10	$ 2	$ 2	$ 462

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