cm:Level1TextBlock: us-gaap:CostMethodInvestmentsDescriptionTextBlock
| Cost-method Investments, Description [Text Block] |
| us-gaap:CostMethodInvestmentsDescriptionTextBlock |
| The entire disclosure for investments accounted for under the cost-method. The carrying amount of such investments may be adjusted, for example, distributions in excess of cost (return of capital) or for other-than-temporary impairments. The cost method and lower-of-cost or market, an adaptation of the cost method, is generally followed for most investments in noncontrolled corporations, in some corporate joint ventures, and to a lesser extent in unconsolidated subsidiaries in which the entity does not have the ability to exercise significant influence. |
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| us-gaap:CostMethodInvestmentsDescriptionTextBlock |
| CostMethodInvestmentsDescription |