cm:Level2TextBlock: us-gaap:DepositContractsPolicy
| Deposit Contracts, Policy [Policy Text Block] |
| us-gaap:DepositContractsPolicy |
| Disclosure of accounting policy for the treatment of funds received from or paid to insureds, insurers and reinsurers on contracts for which the criteria for transferring or assuming insurance risk has not been satisfied by the insurer or reinsurer. |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:DepositContractsPolicy |