Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	$ 127	$ 115
Accumulated Amortization	(24)	(19)
Net Intangible Assets, finite lives	103	96
Developed Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	60	50
Accumulated Amortization	(8)	(5)
Net Intangible Assets, finite lives	52	45
Trademarks [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	11	8
Accumulated Amortization	(1)
Net Intangible Assets, finite lives	10	8
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	56	57
Accumulated Amortization	(15)	(14)
Net Intangible Assets, finite lives	$ 41	$ 43