cm:Concept: us-gaap:PublicUtilitiesAmountOfAllowanceForEarningsOnEquityCapitalizedForRateMakingPurposes
| Public Utilities, Amount of Allowance for Earnings on Equity Capitalized for Rate Making Purposes |
| us-gaap:PublicUtilitiesAmountOfAllowanceForEarningsOnEquityCapitalizedForRateMakingPurposes |
| Discloses the amount of any allowance for earnings on shareholders' investment capitalized for rate making purposes but not for the financial statements. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:PublicUtilitiesAmountOfAllowanceForEarningsOnEquityCapitalizedForRateMakingPurposes |