Commitments and Contingencies - Schedule of Raw Material Purchased under Long Term Purchase Agreements (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2011
Raw Material Purchased Under Long Term Purchase Agreements [Line Items]
Raw material purchased	$ 441		$ 370		$ 358
Reinforcement Materials [Member]
Raw Material Purchased Under Long Term Purchase Agreements [Line Items]
Raw material purchased	371		312		340
Performance Materials [Member]
Raw Material Purchased Under Long Term Purchase Agreements [Line Items]
Raw material purchased	34		47		18
Purification Solutions [Member]
Raw Material Purchased Under Long Term Purchase Agreements [Line Items]
Raw material purchased	34	[1]	4	[1]
Advanced Technologies [Member]
Raw Material Purchased Under Long Term Purchase Agreements [Line Items]
Raw material purchased			6
Other [Member]
Raw Material Purchased Under Long Term Purchase Agreements [Line Items]
Raw material purchased	$ 2		$ 1

[1] The year ended September 30, 2012 includes two months of purchases for Norit.