cm:Concept: us-gaap:DiscontinuanceOfCertainRegulatoryReportingPractices
       
          
          | Discontinuance of Certain Regulatory Reporting Practices | 
       
       
          
          | us-gaap:DiscontinuanceOfCertainRegulatoryReportingPractices | 
       
       
          
          | Describes the entity's reasons for its discontinuation of accounting for the effects of certain types of regulation (primarily costs pertaining to ate-setting) and identifies the portion of its operations to which such application was discontinued. | 
       
       
          
          | cm:Concept | 
       
       
          
          | Text/String (xbrli:stringItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | (no balance type) | 
       
       
          
          | false | 
       
       
          
          | us-gaap:DiscontinuanceOfCertainRegulatoryReportingPractices |