Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016
Income Tax Contingency [Line Items]
Effective tax rate	34.50%	32.30%		33.70%
Uncertain tax positions from increases in positions taken in the current year	$ 1
Ashland
Income Tax Contingency [Line Items]
Obligations to related party				$ 73
Ashland | Other current assets
Income Tax Contingency [Line Items]
Receivables from related party	5			30
Ashland | Accrued expenses and other liabilities
Income Tax Contingency [Line Items]
Obligations to related party	44			2
Ashland | Other long-term liabilities
Income Tax Contingency [Line Items]
Obligations to related party	69			71
Tax Matters Agreement | Ashland
Income Tax Contingency [Line Items]
Obligations to related party	83			66
Tax Matters Agreement | Ashland | Other current assets
Income Tax Contingency [Line Items]
Receivables from related party	5			5
Tax Matters Agreement | Ashland | Accrued expenses and other liabilities
Income Tax Contingency [Line Items]
Obligations to related party	20
Tax Matters Agreement | Ashland | Other long-term liabilities
Income Tax Contingency [Line Items]
Obligations to related party	$ 68			$ 71
Scenario, Forecast
Income Tax Contingency [Line Items]
Effective tax rate			34.60%