| Standard label: | Schedule of Changes in Projected Benefit Obligations [Table Text Block] |
| Name: | us-gaap:ScheduleOfChangesInProjectedBenefitObligationsTableTextBlock |
| Documentation: | Tabular disclosure of the change in the benefit obligation of pension plans and/or other employee benefit plans from the beginning to the end of the period, showing separately, if applicable, the effects of the following: service cost, interest cost, contributions by plan participants, actuarial gains and losses, foreign currency exchange rate changes, benefits paid, plan amendments, business combinations, divestitures, curtailments, settlements, and special and contractual termination benefits. |
| Object type: | cm:Level3TextBlock |
| Data type: | Text Block (HTML) (nonnum:textBlockItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:ScheduleOfChangesInProjectedBenefitObligationsTableTextBlock |
| Examples of this text block disclosure: | ChangesInProjectedBenefitObligations |
| Label | Role | Language |
| Schedule of Changes in Projected Benefit Obligations [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 715 20 50 1 (a) | http://fasb.org/us-gaap/role/ref/legacyRef | 715 |