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, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Interest expense	$ (18)	$ (22)
Less: Equity in earnings of affiliated companies, net of tax	1	1
Unallocated and Other [Member]
Segment Reporting Information [Line Items]
Interest expense	(18)	(22)
Unallocated corporate costs	(13)	(17)
General unallocated income (expense)	7	13
Less: Equity in earnings of affiliated companies, net of tax	1	1
Income from continuing operations before income taxes and equity in earnings of affiliated companies	(31)	(69)
Certain Items [Member]
Segment Reporting Information [Line Items]
Legal and environmental matters and reserves	(5)
Global restructuring activities		(9)
Other certain items	(1)
Total certain items	$ (6)	(42)
Certain Items [Member] | Argentina [Member]
Segment Reporting Information [Line Items]
Controlled currency devaluation and other losses		$ (33)