cm:Concept: us-gaap:ClosedBlockOperationsPolicyholderDividends
| Closed Block Operations, Policyholder Dividends |
| us-gaap:ClosedBlockOperationsPolicyholderDividends |
| An expense for the period representing distributions paid or accrued for the segregated group of participating or dividend-paying policies and contracts along with the assets allocated to them (known as a closed block), which may be presented in a table of closed block operations as part of summarized financial data. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:ClosedBlockOperationsPolicyholderDividends |