cm:Concept: us-gaap:LiabilityForFuturePolicyBenefitRemeasurementGainLoss
| Liability for Future Policy Benefit, Remeasurement Gain (Loss) |
| us-gaap:LiabilityForFuturePolicyBenefitRemeasurementGainLoss |
| Amount of remeasurement gain (loss) on liability for future policy benefit from application of revised benefit ratio as of contract issue. Includes, but is not limited to, remeasurement gain (loss) for annuitization insurance benefit, death and other insurance benefits, and traditional and limited-payment contracts. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:LiabilityForFuturePolicyBenefitRemeasurementGainLoss |