Restructuring - Recorded Restructuring Activities (Detail) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost And Reserve [Line Items]
Restructuring reserve, period expense	$ 3	$ 8
Cost of Sales [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve, period expense	$ 3	1
Selling and Administrative Expenses [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve, period expense		$ 7