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	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Interest expense	$ (53)	$ (54)	$ (53)
Global restructuring activities	(3)	(47)	(21)
Inventories	(50)	51	58
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Interest expense	(53)	(54)	(53)
Unallocated corporate costs	(50)	(45)	(46)
General unallocated income (expense)	(8)	7	11
Less: Equity in earnings of affiliated companies, net of tax	7	3	4
Income from continuing operations before income taxes and equity in earnings of affiliated companies	(121)	(176)	(709)
Certain Item [Member]
Segment Reporting Information [Line Items]
Global restructuring activities	(3)	(47)	(21)
Legal and environmental matters and reserves	1	(17)
Acquisition and integration-related charges			(5)
Employee benefit plan settlement and other charges			(21)
Impairment of goodwill and long-lived assets of Purification Solutions			(562)
Non-recurring gain (loss) on foreign exchange		(11)	(2)
Inventories			(6)
Executive transition costs		(6)
Other certain items	(1)
Total certain items, pre-tax	$ (3)	$ (81)	$ (617)