cm:Concept: us-gaap:DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation |
us-gaap:DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation |
Amount of increase in accumulated postretirement benefit obligation from one-percentage-point increase in assumed health care cost trend rate. |
cm:Concept |
Monetary (xbrli:monetaryItemType) |
For Period (duration) |
Credit |
false |
us-gaap:DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation |