Financial Information by Segments & Geographic Area - Schedule of Performance Segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Performance Materials [Member] Operating Segments [Member]	Sep. 30, 2012 Performance Materials [Member] Operating Segments [Member]	Sep. 30, 2011 Performance Materials [Member] Operating Segments [Member]	Sep. 30, 2013 Performance Materials [Member] Specialty Carbons and Compounds [Member] Operating Segments [Member]	Sep. 30, 2012 Performance Materials [Member] Specialty Carbons and Compounds [Member] Operating Segments [Member]	Sep. 30, 2011 Performance Materials [Member] Specialty Carbons and Compounds [Member] Operating Segments [Member]	Sep. 30, 2013 Performance Materials [Member] Fumed Metal Oxides [Member] Operating Segments [Member]	Sep. 30, 2012 Performance Materials [Member] Fumed Metal Oxides [Member] Operating Segments [Member]	Sep. 30, 2011 Performance Materials [Member] Fumed Metal Oxides [Member] Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	$ 898	$ 903	$ 842	$ 820	$ 848	$ 846	$ 844	$ 762	$ 3,463	$ 3,300	$ 904	$ 914	$ 880	$ 622	$ 664	$ 626	$ 282	$ 250	$ 254