Employee Benefit Plans - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income, Pre-Tax (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]
Net losses (gains)	$ 14	$ (4)	$ (32)
Amortization of prior unrecognized loss			(2)
Total other Comprehensive loss (income)	14	(4)	(34)
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net losses (gains)	(8)	50	8
Prior service (credit) cost	(2)
Amortization of prior unrecognized loss	(4)	(3)	(4)
Other	(27)	(1)	(4)
Total other Comprehensive loss (income)	(41)	46
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net losses (gains)	1	(4)	(6)
Prior service (credit) cost	(11)	3	3
Amortization of prior unrecognized loss	4
Total other Comprehensive loss (income)	$ (6)	$ (1)	$ (3)