cm:Concept: us-gaap:ObligationWithJointAndSeveralLiabilityArrangementAmountOutstanding
| Obligation with Joint and Several Liability Arrangement, Amount Outstanding |
| us-gaap:ObligationWithJointAndSeveralLiabilityArrangementAmountOutstanding |
| Amount outstanding, before the effects of recovery, of obligation under the joint and several liability arrangement. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:ObligationWithJointAndSeveralLiabilityArrangementAmountOutstanding |