Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Goodwill And Intangible Assets [Line Items]
Amortization expense estimated for year one	$ 8		$ 8
Amortization expense estimated for year two	8		8
Amortization expense estimated for year three	8		8
Amortization expense estimated for year four	8		8
Amortization expense estimated for year five	8		8
Cost of Sales, Selling and Administrative Expenses and Research and Technical Expenses [Member]
Goodwill And Intangible Assets [Line Items]
Amortization of intangible assets	$ 2	$ 2	$ 6	$ 5
Minimum [Member]
Goodwill And Intangible Assets [Line Items]
Useful life of intangible assets			10 years
Maximum [Member]
Goodwill And Intangible Assets [Line Items]
Useful life of intangible assets			25 years
Weighted Average [Member]
Goodwill And Intangible Assets [Line Items]
Useful life of intangible assets			18 years