| Standard label: | Defined Benefit Plan, Prescription Drug Benefit, Accumulated Postretirement Benefit Obligation, Decrease for Subsidy |
| Name: | us-gaap:DefinedBenefitPlanPrescriptionDrugBenefitAccumulatedPostretirementBenefitObligationDecreaseForSubsidy |
| Documentation: | Amount of decrease in accumulated postretirement benefit obligation for government subsidy related to prescription drug benefits attributed to past service. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | For Period (duration) |
| Balance type: | Debit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:DefinedBenefitPlanPrescriptionDrugBenefitAccumulatedPostretirementBenefitObligationDecreaseForSubsidy |
| Label | Role | Language |
| Defined Benefit Plan, Prescription Drug Benefit, Accumulated Postretirement Benefit Obligation, Decrease for Subsidy | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 715 60 50 3 (a) | http://fasb.org/us-gaap/role/ref/legacyRef | 715 |