Purification Solutions Goodwill and Long-Lived Assets Impairment Charges - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Goodwill And Intangible Assets [Line Items]
Purification Solutions goodwill impairment charge					$ 352
Long-lived asset impairment charge				$ 23	210
Provision (benefit) for income taxes			$ 35	$ 35	86
Purification Solutions [Member]
Goodwill And Intangible Assets [Line Items]
Purification Solutions goodwill impairment charge		$ 353			352
Decrease in goodwill impairment charge during the period	$ 1
Impairment loss of indefinite lived Intangibles					39
Impairment charges of definite lived Intangible assets		119
Long-lived asset impairment charge					210
Provision (benefit) for income taxes					80
Purification Solutions [Member] | Property, Plant and Equipment [Member]
Goodwill And Intangible Assets [Line Items]
Long-lived asset impairment charge	$ 1	$ 51			$ 52