Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Sep. 30, 2023
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	$ 104	$ 101
Accumulated Amortization	(43)	(41)
Net Intangible Assets, finite lives	61	60
Developed Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	35	34
Accumulated Amortization	(11)	(10)
Net Intangible Assets, finite lives	24	24
Trademarks [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	2	2
Accumulated Amortization	(1)	(1)
Net Intangible Assets, finite lives	1	1
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	67	65
Accumulated Amortization	(31)	(30)
Net Intangible Assets, finite lives	$ 36	$ 35