Union Contracts (Details)	Jun. 30, 2018 employees
Middletown Works [Member]
Concentration Risk [Line Items]
Entity Number of Employees	1,720
Ashland Works [Member]
Concentration Risk [Line Items]
Entity Number of Employees	260
Mountain State Carbon [Member]
Concentration Risk [Line Items]
Entity Number of Employees	200
Butler Works [Member]
Concentration Risk [Line Items]
Entity Number of Employees	1,130
Coshocton Works [Member]
Concentration Risk [Line Items]
Entity Number of Employees	310

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.

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