cm:Concept: us-gaap:DefinedBenefitPlanBenefitObligationPaymentForSettlement
| Defined Benefit Plan, Benefit Obligation, Payment for Settlement |
| us-gaap:DefinedBenefitPlanBenefitObligationPaymentForSettlement |
| Amount of payment, which decreases benefit obligation of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract. Excludes decreases to benefit obligation for remeasurement due to settlement. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:DefinedBenefitPlanBenefitObligationPaymentForSettlement |