cm:Concept: us-gaap:IncreaseDecreaseInRecoverableRefundableGasCosts
| Increase (Decrease) in Recoverable Refundable Gas Costs |
| us-gaap:IncreaseDecreaseInRecoverableRefundableGasCosts |
| The increase (decrease) during the reporting period in the asset or liability created by a public utility's ability to recover gas costs that are higher or lower than the basic cost included in rate payer calculations. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:IncreaseDecreaseInRecoverableRefundableGasCosts |