cm:Concept: us-gaap:IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions
| Income (Loss) from Equity Method Investments, Net of Dividends or Distributions |
| us-gaap:IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions |
| This element represents the undistributed income (or loss) of equity method investments, net of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporations; such investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:IncomeLossFromEquityMethodInvestmentsNetOfDividendsOrDistributions |