cm:Level3TextBlock: us-gaap:ScheduleOfUnderlyingAssetsOfRepurchaseAgreementsWhenAmountOfRepurchaseAgreementsExceeds10PercentOfAssetsTextBlock
| Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets [Table Text Block] |
| us-gaap:ScheduleOfUnderlyingAssetsOfRepurchaseAgreementsWhenAmountOfRepurchaseAgreementsExceeds10PercentOfAssetsTextBlock |
| Tabular disclosure, as of the most recent balance sheet date, of securities or other assets sold under repurchase agreements when this amount exceeds 10 percent of total assets. Disclosure may include the following: the type of securities or assets sold under agreements to repurchase, the carrying amount, market value (including accrued interest plus any cash or other assets on deposit. The information is segregated into securities maturing (1) overnight; (2) term up to 30 days; (3) term of 30 to 90 days; (4) term over 90 days; (5) demand. |
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| us-gaap:ScheduleOfUnderlyingAssetsOfRepurchaseAgreementsWhenAmountOfRepurchaseAgreementsExceeds10PercentOfAssetsTextBlock |