cm:Level2TextBlock: us-gaap:PensionAndOtherPostretirementPlansNonpensionBenefitsPolicy
| Pension and Other Postretirement Plans, Nonpension Benefits, Policy [Policy Text Block] |
| us-gaap:PensionAndOtherPostretirementPlansNonpensionBenefitsPolicy |
| Disclosure of accounting policy for plans, other than pension plans, that provide postretirement benefits (including both defined benefit and defined contribution plans). This accounting policy may address (1) the types of plans sponsored by the entity, and the benefits provided by each plan (2) groups that participate in (or are covered by) each plan (3) how plan assets, liabilities and expenses are measured, including the use of any actuaries and (4) significant assumptions used by the entity to value plan assets and liabilities and how such assumptions are derived. |
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| us-gaap:PensionAndOtherPostretirementPlansNonpensionBenefitsPolicy |