cm:Level2TextBlock: us-gaap:RegulatoryEnvironmentalCostsPolicy
| Regulatory Environmental Costs, Policy [Policy Text Block] |
| us-gaap:RegulatoryEnvironmentalCostsPolicy |
| Disclosure of accounting policy for liabilities for remediation of environmental matters. The accounting policy may specify the conditions under which rate actions of a regulator provide reasonable assurance of the existence of an asset pertaining thereto. |
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| us-gaap:RegulatoryEnvironmentalCostsPolicy |