Financial Information by Segment - Sales of Equity Method Affiliate and Discounting Charges for Certain Notes Receivable (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Net sales	$ 705	$ 621	$ 1,994	$ 1,792
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Net sales	26	27	81	80
Unallocated and Other [Member] | Royalties, 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	(4)		(6)
Unallocated and Other [Member] | Shipping and Handling Costs [Member]
Segment Reporting Information [Line Items]
Net sales	$ 30	$ 27	$ 87	$ 80