Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Sep. 30, 2016
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	$ 147	$ 154
Accumulated Amortization	(16)	(14)
Net Intangible Assets, finite lives	131	140
Developed Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	46	48
Accumulated Amortization	(5)	(4)
Net Intangible Assets, finite lives	41	44
Trademarks [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	15	16
Accumulated Amortization	(1)	(1)
Net Intangible Assets, finite lives	14	15
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	86	90
Accumulated Amortization	(10)	(9)
Net Intangible Assets, finite lives	$ 76	$ 81