Restructuring - Recorded Restructuring Activities (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Restructuring Cost And Reserve [Line Items]
Restructuring reserve, period expense	$ 21	$ 29	$ 35
Cost of Sales [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve, period expense	10	12	28
Selling and Administrative Expenses [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring reserve, period expense	$ 11	$ 17	$ 7