Income Taxes - Components of Deferred Income Taxes (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016
Components Of Deferred Tax Assets [Abstract]
Deferred expenses	$ 22	$ 25
Intangible assets	43	45
Inventory	14	13
Other	14	4
Pension and other benefits	59	83
Net operating loss carry-forwards	149	144
Foreign tax credit carry-forwards	132	63
R&D credit carry-forwards	38	35
Other business credit carry-forwards	37	41
Subtotal	508	453
Valuation allowance	(168)	(177)
Total deferred tax assets	340	276
Property, plant and equipment	(116)	(101)
Unremitted earnings of non-U.S. subsidiaries	(12)
Total deferred tax liabilities	$ (128)	$ (101)