cm:Concept: us-gaap:PreferredStockRedemptionAmountFutureRedeemableSecurities
| Preferred Stock, Redemption Amount, Future Redeemable Securities |
| us-gaap:PreferredStockRedemptionAmountFutureRedeemableSecurities |
| The redemption (or callable) amount of redeemable preferred stock, excluding currently redeemable preferred stock. Includes amounts representing dividends not declared or paid but which will be payable under the redemption features or for which ultimate payment is solely within the control of the issuer. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:PreferredStockRedemptionAmountFutureRedeemableSecurities |