cm:Concept: us-gaap:CoalIndustryRetireeHealthBenefitActOf1992MethodOfAccountingAdopted
Coal Industry Retiree Health Benefit Act of 1992, Method of Accounting Adopted |
us-gaap:CoalIndustryRetireeHealthBenefitActOf1992MethodOfAccountingAdopted |
Description of method of accounting adopted for obligation to provide medical and death benefits under Coal Industry Retiree Health Benefit Act of 1992. |
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us-gaap:CoalIndustryRetireeHealthBenefitActOf1992MethodOfAccountingAdopted |