Goodwill and Intangible Assets - Schedule of Goodwill Balances (Detail) $ in Millions	9 Months Ended
	Jun. 30, 2017 USD ($)
Goodwill And Intangible Assets [Line Items]
Beginning balance	$ 152
Foreign currency impact	1
Ending balance	153
Reinforcement Materials [Member]
Goodwill And Intangible Assets [Line Items]
Beginning balance	52
Foreign currency impact	1
Ending balance	53
Performance Chemicals [Member]
Goodwill And Intangible Assets [Line Items]
Beginning balance	9
Ending balance	9
Purification Solutions [Member]
Goodwill And Intangible Assets [Line Items]
Beginning balance	91
Ending balance	$ 91