Acquisitions - Schedule of Allocation of Purchase Price Based on Estimates of Fair Value of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Millions	Sep. 30, 2020	[1]	Apr. 01, 2020	Sep. 30, 2019	[1]
Assets
Cash			$ 1
Accounts Receivable			8
Inventories			4
Prepaid expenses and other current assets			2
Property, plant and equipment			38
Intangible assets			15
Goodwill	$ 134		45	$ 90
Deferred tax asset			1
Other assets			2
Total assets acquired			116
Liabilities
Accounts payable and accrued liabilities			(12)
Long-term debt			(13)
Other liabilities			(6)
Total liabilities assumed			(31)
Cash consideration paid			$ 85

[1] ^{The Company incurred $444 million accumulated impairment losses associated with the goodwill of the Purification Solutions segment as of both September 30, 2020 and 2019. There were no accumulated impairment losses associated with the goodwill of the Reinforcement Materials or Performance Chemicals segments.}