cm:Concept: us-gaap:IncreaseDecreaseInBalancingAccountUtility
| Increase (Decrease) in Balancing Account, Utility |
| us-gaap:IncreaseDecreaseInBalancingAccountUtility |
| The increase (decrease) during the reporting period in the asset created by the regulatory convention in which costs and revenues associated with certain utility expenses (such as fuel) are accumulated but on which no return is earned. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:IncreaseDecreaseInBalancingAccountUtility |