Employee Benefit Plans - Amounts Recognized in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liabilities	$ (122)	$ (173)
U.S. Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	1
Current liabilities	(1)
Noncurrent liabilities	(4)	(18)
Foreign Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	12	8
Current liabilities	(1)	(1)
Noncurrent liabilities	(69)	(102)
U. S. Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(3)	(3)
Noncurrent liabilities	(30)	(34)
Foreign Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(1)	(1)
Noncurrent liabilities	$ (19)	$ (19)