Purification Solutions Goodwill and Long-Lived Assets Impairment Charges - Additional Information (Detail) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2018 USD ($)	Mar. 31, 2018 USD ($)
Goodwill And Intangible Assets [Line Items]
Goodwill impairment charge	$ 92	$ 92
Long-lived assets impairment charge	162	162
Assets impairment charges income tax benefit	30
Reducing of impairment charges and restructuring costs	1
Purification Solutions [Member]
Goodwill And Intangible Assets [Line Items]
Goodwill impairment charge	92
Lower of cost or market reserve inventory	13	$ 13
Long-lived assets impairment charge	162
Impairment charges of definite lived Intangible assets	64
Purification Solutions [Member] | Property, Plant and Equipment [Member]
Goodwill And Intangible Assets [Line Items]
Long-lived assets impairment charge	$ 98