cm:Concept: us-gaap:ContractWithCustomerAssetReclassifiedToReceivable
| Contract with Customer, Asset, Reclassified to Receivable |
| us-gaap:ContractWithCustomerAssetReclassifiedToReceivable |
| Amount of decrease in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time from transfer to receivable due to right to consideration becoming unconditional. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:ContractWithCustomerAssetReclassifiedToReceivable |