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
	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Interest expense	$ (12)	$ (14)
Global restructuring activities	(3)	(8)
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Interest expense	(12)	(14)
Unallocated corporate costs	(13)	(10)
General unallocated income (expense)	(5)	(1)
Income from continuing operations before income taxes and equity in earnings of affiliated companies	(41)	(36)
Certain Items [Member]
Segment Reporting Information [Line Items]
Employee benefit plan settlement and other charges	(6)	(2)
Global restructuring activities	(3)	(8)
Acquisition and integration-related charges	(1)	(1)
Legal and environmental matters and reserves		1
Other	(1)	(1)
Total certain items, pre-tax	$ (11)	$ (11)