| Name | CoalIndustryRetireeHealthBenefitActOf1992MethodOfAccountingAdopted |
|---|---|
| Namespace | http://fasb.org/us-gaap/2020-01-31 |
| Prefix | us-gaap |
| Data type | xbrli:stringItemType |
| Period type | duration |
| Substitution Group | xbrli:item |
| Balance | None |
| Nillable | True |
| Abstract | False |
| Text | Lang | Role | Container role |
|---|---|---|---|
| Coal Industry Retiree Health Benefit Act of 1992, Method of Accounting Adopted | en-US | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Description of method of accounting adopted for obligation to provide medical and death benefits under Coal Industry Retiree Health Benefit Act of 1992. | en-US | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |
| Name | Value | Role |
|---|---|---|
| Publisher | FASB | http://www.xbrl.org/2003/role/disclosureRef |
| Name | Accounting Standards Codification | http://www.xbrl.org/2003/role/disclosureRef |
| Topic | 930 | http://www.xbrl.org/2003/role/disclosureRef |
| SubTopic | 715 | http://www.xbrl.org/2003/role/disclosureRef |
| Section | 50 | http://www.xbrl.org/2003/role/disclosureRef |
| Paragraph | 1 | http://www.xbrl.org/2003/role/disclosureRef |
| URI | http://asc.fasb.org/extlink&oid=6473690&loc=d3e23744-110275 | http://www.xbrl.org/2003/role/disclosureRef |
| Name | Relation Type | Role | |
|---|---|---|---|
us-gaap:CoalIndustryRetireeHealthBenefitActOf1992Abstract | parent-child | http://fasb.org/us-gaap/role/disclosure/CompensationRelatedCostsRetirementBenefits |