cm:Concept: us-gaap:LiabilitiesSubjectToCompromiseExpenseReversalOfExpenseForLiabilities
| Liabilities Subject to Compromise, Expense (Reversal of Expense) for Liabilities |
| us-gaap:LiabilitiesSubjectToCompromiseExpenseReversalOfExpenseForLiabilities |
| Amount of expense (reversal of expense) related to liabilities subject to compromise since the bankruptcy filing date. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:LiabilitiesSubjectToCompromiseExpenseReversalOfExpenseForLiabilities |