cm:Concept: us-gaap:IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet
| Increase (Decrease) in Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Net |
| us-gaap:IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet |
| The net cash inflow or outflow from the fund lent to other financial institution arising from the excess in reserve deposited at Federal Reserve Bank to meet legal requirement. This borrowing is usually contracted on an overnight basis at an agreed rate of interest. Also include cash inflow or outflow from investment sold under the agreement to reacquire such investment. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:IncreaseDecreaseInFederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseNet |