| Standard label: | Accrual for Environmental Loss Contingencies, Discount |
| Name: | us-gaap:AccrualForEnvironmentalLossContingenciesDiscount |
| Documentation: | Amount of imputed interest necessary to reduce (reconcile) the undiscounted amount of the accrual for environmental loss contingencies to the present value. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Debit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:AccrualForEnvironmentalLossContingenciesDiscount |
| Label | Role | Language |
| Accrual for Environmental Loss Contingencies, Discount | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 450 20 S99 1 (SAB Topic 5.Y.Q1) | http://fasb.org/us-gaap/role/ref/legacyRef | 450 |