cm:Level2TextBlock: us-gaap:TransfersAndServicingOfFinancialAssetsTransfersOfFinancialAssetsAggregationPolicy
| Transfers and Servicing of Financial Assets, Transfers of Financial Assets, Aggregation, Policy [Policy Text Block] |
| us-gaap:TransfersAndServicingOfFinancialAssetsTransfersOfFinancialAssetsAggregationPolicy |
| Disclosure of accounting policy for aggregating similar transfers. Disclosures may be aggregated for similar transfers if separate reporting of each transfer would not provide more useful information to financial statement users. Describes how an entity determines how much detail it must provide and how it information for assets with different risk characteristics. |
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| us-gaap:TransfersAndServicingOfFinancialAssetsTransfersOfFinancialAssetsAggregationPolicy |