Supplementary Financial Statement Information (Details6) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Ashland Works Hot End [Member]
Restructuring Cost and Reserve [Line Items]
Costs for Temporarily Idled Operations	$ 5.4	$ 5.6

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_RestructuringCostAndReserveLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration