cm:Concept: us-gaap:TradeReceivablesHeldForSaleReconciliationToCashFlowAdditionsToHeldForSale
| Trade Receivables Held-for-sale, Reconciliation to Cash Flow, Additions to Held-for-sale |
| us-gaap:TradeReceivablesHeldForSaleReconciliationToCashFlowAdditionsToHeldForSale |
| Amount of additions to trade receivables held-for-sale, after allowance for bad debt, that are not part of a disposal group. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:TradeReceivablesHeldForSaleReconciliationToCashFlowAdditionsToHeldForSale |