Goodwill and Intangible Assets - Schedule of Intangible Assets (Detail) - USD ($) $ in Millions		Dec. 31, 2021	Sep. 30, 2021
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives		$ 98	$ 133
Accumulated Amortization		(28)	(33)
Net Intangible Assets, finite lives		70	100
Developed Technologies [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	[1]	36	62
Accumulated Amortization	[1]	(7)	(12)
Net Intangible Assets, finite lives	[1]	29	50
Trademarks [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives	[1]	2	11
Accumulated Amortization	[1]		(1)
Net Intangible Assets, finite lives	[1]	2	10
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Value, finite lives		60	60
Accumulated Amortization		(21)	(20)
Net Intangible Assets, finite lives		$ 39	$ 40

[1] Developed technologies intangible assets with a carrying value of $25 million and accumulated amortization of $5 million and trademark intangible assets with a carrying value of $8 million and accumulated amortization of $1 million related to the Purification Solutions business were classified as assets held for sale as of December 31, 2021.