Pension and Postretirement Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
United States Pension Plan of US Entity
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9	$ 17	$ 24	$ 52
Interest cost	30	34	91	103
Expected return on plan assets	(46)	(51)	(136)	(154)
Amortization of prior service cost (credit)	0	0	0	1
Net periodic benefit cost (credit)	(7)	0	(21)	2
Foreign Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	8	20	23
Interest cost	11	14	35	41
Expected return on plan assets	(13)	(15)	(39)	(42)
Amortization of prior service cost (credit)	0	1	0	1
Net periodic benefit cost (credit)	5	8	16	23
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	3
Interest cost	2	3	7	9
Expected return on plan assets	(3)	(3)	(9)	(9)
Amortization of prior service cost (credit)	0	(2)	(1)	(5)
Net periodic benefit cost (credit)	$ 0	$ (1)	$ (1)	$ (2)