Employee Benefit Plans - Net Periodic Defined Benefit Pension and Other Postretirement Benefit Costs (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 2	$ 6
Interest cost	7	7	6
Expected return on plan assets	(11)	(10)	(10)
Net losses			1
Settlements or Curtailments cost			1
Net periodic (benefit) cost	(3)	(1)	4
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	9	9	9
Interest cost	11	16	15
Expected return on plan assets	(14)	(19)	(18)
Amortization of prior service cost	3
Net losses	4	3	4
Settlements or Curtailments cost	18		2
Net periodic (benefit) cost	31	9	12
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	2	2	2
Amortization of prior service cost	(4)	(3)	(3)
Net periodic (benefit) cost	(2)	(1)	(1)
Foreign Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	1	1
Net periodic (benefit) cost	$ 1	$ 1	$ 1