cm:Concept: us-gaap:NetAmountAtRiskByProductAndGuaranteeGuaranteedMinimumReturnRate
| Net Amount at Risk by Product and Guarantee, Guaranteed Minimum Return Rate |
| us-gaap:NetAmountAtRiskByProductAndGuaranteeGuaranteedMinimumReturnRate |
| Rate of guaranteed minimum return on deposits made to contracts reported in separate accounts maintained by an insurance entity. |
| cm:Concept |
| Percent (num:percentItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:NetAmountAtRiskByProductAndGuaranteeGuaranteedMinimumReturnRate |