Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
U.S. Plans Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0		$ 0	$ 13
Interest cost	9	$ 9	27	30
Expected return on assets	(17)	(17)	(52)	(52)
Amortization of:
Prior service credit			0	(1)
Actuarial loss (gain)	3	2	11	6
Curtailment gain			0	(8)
Settlement loss	9	0	22	0
Total net periodic benefit cost	4	(6)	8	(12)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	0	0	0	0
Expected return on assets	0	0	0	0
Amortization of:
Prior service credit			(1)	(2)
Actuarial loss (gain)	(1)	(1)	(1)	(1)
Curtailment gain			0	0
Settlement loss	0	0	0	0
Total net periodic benefit cost	(1)	$ (1)	(2)	$ (3)
Non-U.S. Plans Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	2		5
Interest cost	3		8
Expected return on assets	(4)		(12)
Amortization of:
Prior service credit			0
Actuarial loss (gain)	0		1
Curtailment gain			0
Settlement loss	0		0
Total net periodic benefit cost	$ 1		$ 2