Restructuring - Additional Information (Detail) $ in Millions	1 Months Ended		3 Months Ended				9 Months Ended		12 Months Ended
	Oct. 31, 2017 USD ($) ProductionUnit Employees	Oct. 31, 2015 Employees	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)
Restructuring Cost And Reserve [Line Items]
Proceeds from sale of land							$ 13
Marshall, Texas Plan [Member]
Restructuring Cost And Reserve [Line Items]
Number of idled production units | ProductionUnit	3
Number of production units | ProductionUnit	7
Number of employees termination | Employees	40
Restructuring expected charges	$ 1
Accelerated depreciation charges							1
Marshall, Texas Plan [Member] | Non-Cash Accelerated Depreciation [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expected charges	1
Marshall, Texas Plan [Member] | Severance Costs [Member] | Maximum [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring expected charges	$ 1
Operational Restructuring [Member]
Restructuring Cost And Reserve [Line Items]
Number of employees termination | Employees		300
Pre-tax charge to earnings							1	$ 1
Operational Restructuring [Member] | Merak [Member]
Restructuring Cost And Reserve [Line Items]
Proceeds from sale of land				$ 9
Net benefit to earnings				$ 11
Operational Restructuring [Member] | Thane, India [Member]
Restructuring Cost And Reserve [Line Items]
Proceeds from sale of land							32
Net benefit to earnings							32
Operational Restructuring [Member] | Accounts Payable and Accrued Liabilities [Member] | Merak [Member]
Restructuring Cost And Reserve [Line Items]
Refundable cash deposit					$ 4
Operational Restructuring [Member] | Accounts Payable and Accrued Liabilities [Member] | Thane, India [Member]
Restructuring Cost And Reserve [Line Items]
Refundable cash deposit			$ 3			$ 3
Operational Restructuring [Member] | Scenario Forecast [Member]
Restructuring Cost And Reserve [Line Items]
Pre-tax charge to earnings									$ 1
Operational Restructuring [Member] | Maximum [Member] | Merak [Member]
Restructuring Cost And Reserve [Line Items]
Pre-tax charge to earnings								$ 1
Operational Restructuring [Member] | Severance Costs [Member] | Maximum [Member]
Restructuring Cost And Reserve [Line Items]
Accrued severance charges			1				1
Closure Of Carbon Black Facility | Severance Costs [Member] | Maximum [Member]
Restructuring Cost And Reserve [Line Items]
Accrued severance charges			$ 1				1
Previous Actions and Sites Pending Sale [Member]
Restructuring Cost And Reserve [Line Items]
Severance charges							$ 1