Financial Information by Segment - Schedule of Income (Loss) from Continuing Operations before Income Taxes and Equity in Earnings of Affiliated Companies for Unallocated and Other (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Interest expense	$ (13)	$ (14)	$ (26)	$ (27)
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Interest expense	(13)	(14)	(26)	(27)
Total certain items, pre-tax		1		(57)
Unallocated corporate costs	(14)	(12)	(26)	(25)
General unallocated income (expense)	(1)		4	5
Less: Equity in earnings of affiliated companies, net of tax	(1)	(1)	(3)	(1)
Income from continuing operations before income taxes and equity in earnings of affiliated companies	$ (29)	$ (26)	$ (51)	$ (105)