cm:Level2TextBlock: us-gaap:ImpairedFinancingReceivablePolicyPolicyTextBlock
| Impaired Financing Receivable, Policy [Policy Text Block] |
| us-gaap:ImpairedFinancingReceivablePolicyPolicyTextBlock |
| Disclosure of accounting policy for recognizing interest income on impaired financing receivables, including how cash receipts are recorded, the policy for determining which loans the entity assess for impairment, and the factors the creditor considered in determining that the financing receivable is impaired. |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ImpairedFinancingReceivablePolicyPolicyTextBlock |