cm:Concept: us-gaap:EquityMethodInvestmentUnrealizedIntercompanyProfitLossNotEliminatedAmount
| Equity Method Investment, Unrealized Intercompany Profit (Loss) Not Eliminated, Amount |
| us-gaap:EquityMethodInvestmentUnrealizedIntercompanyProfitLossNotEliminatedAmount |
| This item represents the amount of unrealized intercompany profits and losses on transactions between the Entity and unconsolidated subsidiaries (including certain corporate joint ventures, and noncontrolled corporations), accounted for under the equity method of accounting, which have not been eliminated in preparing the Entity's financial statements. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:EquityMethodInvestmentUnrealizedIntercompanyProfitLossNotEliminatedAmount |