cm:Concept: us-gaap:PublicUtilitiesPropertyPlantAndEquipmentAmountOfIndirectDisallowanceOfCostsOfRecentlyCompletedPlants
| Public Utilities, Property, Plant and Equipment, Amount of Indirect Disallowance of Costs of Recently Completed Plants |
| us-gaap:PublicUtilitiesPropertyPlantAndEquipmentAmountOfIndirectDisallowanceOfCostsOfRecentlyCompletedPlants |
| The amount of indirect disallowance of costs of a recently completed plant. When it becomes probable that part of the cost of a recently completed plant will be disallowed for rate-making purposes and a reasonable estimate of the amount of the disallowance can be made, the estimated amount of the probable disallowance is deducted from the reported cost of the plant and recognized as a loss. If part of the cost is explicitly, but indirectly, disallowed (for example, by an explicit disallowance of return on investment on a portion of the plant), an equivalent amount of cost is deducted from the reported cost of the plant and recognized as a loss. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:PublicUtilitiesPropertyPlantAndEquipmentAmountOfIndirectDisallowanceOfCostsOfRecentlyCompletedPlants |