Commitments and Contingent Liabilities - Narrative (Details)	May 01, 2020 employee
Murray \| Settlement Agreement Between Murray And UMWA [Member]
Loss Contingencies [Line Items]
Number of retirees	2,159

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