| Standard label: | Schedule of Net Benefit Costs [Table Text Block] |
| Name: | us-gaap:ScheduleOfNetBenefitCostsTableTextBlock |
| Documentation: | Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. |
| 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:ScheduleOfNetBenefitCostsTableTextBlock |
| Examples of this text block disclosure: | NetBenefitCosts |
| Label | Role | Language |
| Schedule of Net Benefit Costs [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 715 20 50 1 (h) | http://fasb.org/us-gaap/role/ref/legacyRef | 715 |