Restructuring - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2020
Restructuring Cost And Reserve [Line Items]
Restructuring charges	$ 4	$ 1	$ 3
Reorganization Actions [Member]
Restructuring Cost And Reserve [Line Items]
Severance costs				$ 20	$ 15	$ 17
Accrued severance charges	3			3
Restructuring charges expected throughout rest of 2021 related to site demolition costs	2			2
Restructuring charges expected thereafter fiscal year related to severance and site demolition costs	4			4
Restructuring cash payments of fiscal year	17				$ 10	13
Restructuring cash payments through the reminder of fiscal 2021	1
Restructuring future cash payments thereafter fiscal year	8			8
Purification Solutions Transformation Plan [Member]
Restructuring Cost And Reserve [Line Items]
Accrued severance charges	1			1
Restructuring cash payments of fiscal year				11		9
Restructuring cash payments through the reminder of fiscal 2021				2
Restructuring future cash payments thereafter fiscal year	1			1
Restructuring charges				15		$ 11
Purification Solutions Transformation Plan [Member] | Manufacturing Facility [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring charges expected throughout rest of 2021 related to decommissioning costs	1			1
Restructuring charges expected thereafter fiscal year related to decommissioning costs	$ 1			$ 1