Pension and Postretirement Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
United States Pension Plan of US Entity
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 4	$ 9	$ 12	$ 24
Interest cost	26	30	76	91
Expected return on plan assets	(47)	(46)	(140)	(136)
Net periodic benefit cost (credit)	(17)	(7)	(52)	(21)
Foreign Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	8	7	17	20
Interest cost	11	11	31	35
Expected return on plan assets	(15)	(13)	(41)	(39)
Net periodic benefit cost (credit)	4	5	7	16
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	2
Interest cost	2	2	5	7
Expected return on plan assets	(3)	(3)	(8)	(9)
Amortization of prior service credit	0	0	(1)	(1)
Net periodic benefit cost (credit)	$ 0	$ 0	$ (2)	$ (1)