Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	$ 486	$ 423
Less accumulated depreciation	(257)	(210)
Net Property, Plant and Equipment	229	213
Land
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	11	11
Buildings and Improvements
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	109	99
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	11	10
Computer Hardware and Software
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	302	262
Construction in Progress
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	42	30
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Gross Property, Plant and Equipment	$ 11	$ 11