Financial Information by Segment - Sales of Equity Method Affiliate and Discounting Charges for Certain Notes Receivable (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Net sales	$ 568	$ 694	$ 1,171	$ 1,506
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Net sales	18	20	53	51
Unallocated and Other [Member] | Royalties, Other Operating Revenues, the Impact of Unearned Revenue, the Removal of 100% of the Sales of an Equity Method Affiliate and Discounting Charges for Certain Notes Receivable [Member]
Segment Reporting Information [Line Items]
Net sales	(9)	(8)		(4)
Unallocated and Other [Member] | Shipping and Handling Costs [Member]
Segment Reporting Information [Line Items]
Net sales	$ 27	$ 28	$ 53	$ 55