Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Sep. 30, 2016
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	$ 152	$ 154
Accumulated Amortization	(18)	(14)
Net Intangible Assets, finite lives	134	140
Developed Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	47	48
Accumulated Amortization	(5)	(4)
Net Intangible Assets, finite lives	42	44
Trademarks [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	14	16
Accumulated Amortization	(1)	(1)
Net Intangible Assets, finite lives	13	15
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	91	90
Accumulated Amortization	(12)	(9)
Net Intangible Assets, finite lives	$ 79	$ 81