Employee Benefit Plans - Net Periodic Defined Benefit Pension and Other Postretirement Benefit Costs (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 1	$ 2
Interest cost	4	7	7
Expected return on plan assets	(10)	(11)	(10)
Net periodic (benefit) cost	(5)	(3)	(1)
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	9	9
Interest cost	8	11	16
Expected return on plan assets	(14)	(14)	(19)
Amortization of prior service cost		3
Net losses	3	4	3
Settlements or Curtailments cost	1	18
Net periodic (benefit) cost	6	31	9
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	2	2
Amortization of prior service cost	(3)	(4)	(3)
Settlements or Curtailments cost	(1)
Net periodic (benefit) cost	(3)	(2)	(1)
Foreign Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	1	1
Net periodic (benefit) cost	$ 1	$ 1	$ 1