cm:Level3TextBlock: us-gaap:ScheduleOfDefinedBenefitPlansDisclosuresTextBlock
| Schedule of Defined Benefit Plans Disclosures [Table Text Block] |
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| Tabular disclosure of one or more of the entity's defined benefit pension plans or one or more other defined benefit postretirement plans, separately for pension plans and other postretirement benefit plans including the entity's schedule of fair value of plan assets for defined benefit or other postretirement plans. |
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| DefinedBenefitPlanBenefitObligationRollForward |