Financial Information by Segment - Schedule of Income (Loss) from Continuing Operations before Taxes for Unallocated and Other (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]
Interest expense	$ (14)	$ (14)	$ (27)	$ (27)
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Interest expense	(14)	(14)	(27)	(27)
Total certain items, pre-tax	1	(6)	(57)	(32)
Equity in (earnings) loss of affiliated companies, net of tax	(1)	(2)	(1)	(3)
Unallocated corporate costs	(12)	(11)	(25)	(23)
General unallocated income (expense)		3	5	9
Income from continuing operations before income taxes and equity in earnings of affiliated companies	$ (26)	$ (30)	$ (105)	$ (76)