cm:Axis: us-gaap:FinancialSupportToNonconsolidatedLegalEntityAxis
| Financial Support to Nonconsolidated Legal Entity [Axis] |
| us-gaap:FinancialSupportToNonconsolidatedLegalEntityAxis |
| Information by financial support arrangement provided to a nonconsolidated legal entity that is required to comply with or operate in accordance with requirements that are similar to those included in Rule 2a-7 of the Investment Company Act of 1940 for registered money market funds. |
| cm:Axis |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:FinancialSupportToNonconsolidatedLegalEntityAxis |