cm:Level2TextBlock: us-gaap:RegulatoryIncomeTaxesPolicy
| Regulatory Income Taxes, Policy [Policy Text Block] |
| us-gaap:RegulatoryIncomeTaxesPolicy |
| Disclosure of accounting policy for income taxes, including investment tax credits, and the related regulatory treatment (for example, whether deferred income tax accounting - normalization - is allowed in rate making). |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
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| us-gaap:RegulatoryIncomeTaxesPolicy |