cm:Level2TextBlock: us-gaap:ReceivablesAndPortionsOfSecuritizationsThatCanBePrepaidAtPotentialLossPolicyPolicyTextBlock
| Receivables and Portions of Securitizations that can be Prepaid at Potential Loss, Policy [Policy Text Block] |
| us-gaap:ReceivablesAndPortionsOfSecuritizationsThatCanBePrepaidAtPotentialLossPolicyPolicyTextBlock |
| Disclosure of accounting policy for classification and method of accounting for interest-only strips, loans, other receivables, or retained interests in securitizations that can be contractually prepaid or otherwise settled in a way that the holder would not recover substantially all of its recorded investment. |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:ReceivablesAndPortionsOfSecuritizationsThatCanBePrepaidAtPotentialLossPolicyPolicyTextBlock |