Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions	Jun. 30, 2025	Sep. 30, 2024
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	$ 105	$ 96
Accumulated Amortization	(49)	(43)
Net Intangible Assets, finite lives	56	53
Developed Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	41	34
Accumulated Amortization	(14)	(12)
Net Intangible Assets, finite lives	27	22
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	62	60
Accumulated Amortization	(34)	(30)
Net Intangible Assets, finite lives	$ 28	$ 30