| Standard label: | Schedule of Environmental Loss Contingencies by Site [Table Text Block] |
| Name: | us-gaap:ScheduleOfEnvironmentalLossContingenciesBySiteTextBlock |
| Documentation: | Tabular disclosure of environmental loss contingencies by individual site. Does not include loss contingencies that are not environmental in nature. |
| 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:ScheduleOfEnvironmentalLossContingenciesBySiteTextBlock |
| Examples of this text block disclosure: | EnvironmentalLossContingenciesBySite |
| Label | Role | Language |
| Schedule of Environmental Loss Contingencies by Site [Table Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 410 30 50 7 | http://fasb.org/us-gaap/role/ref/legacyRef | 410 |
| FASB Accounting Standards Codification 410 30 50 10 (d) | http://fasb.org/us-gaap/role/ref/legacyRef | 410 |
| FASB Accounting Standards Codification 410 30 50 11 | http://fasb.org/us-gaap/role/ref/legacyRef | 410 |
| FASB Accounting Standards Codification 410 30 50 12 | http://fasb.org/us-gaap/role/ref/legacyRef | 410 |
| FASB Accounting Standards Codification 450 20 S99 1 (SAB TOPIC 5.Y.Q2) | http://fasb.org/us-gaap/role/ref/legacyRef | 450 |