cm:Concept: us-gaap:AssetsDesignatedToClosedBlockPolicyLoans
| Assets Designated to Closed Block, Policy Loans |
| us-gaap:AssetsDesignatedToClosedBlockPolicyLoans |
| Carrying amount of loans to policy holders secured by benefits under insurance policies that are allocated to the segregated group of participating or dividend-paying policies and contracts identified as the closed block. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:AssetsDesignatedToClosedBlockPolicyLoans |