cm:Member: us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |
| us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember |
| Debt securities collateralized by real estate mortgage loans (mortgages), issued by US Government Sponsored Enterprises, such as Federal Home Loan Mortgage Corporation (FHLMC or Freddie Mac). |
| cm:Member |
| [Member] (nonnum:domainItemType) |
| For Period (duration) |
| (no balance type) |
| true |
| us-gaap:MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember |