cm:Concept: us-gaap:DebtSecuritiesAvailableForSaleMaturityWithinOneYearWeightedAverageYield
| Debt Securities, Available-for-sale, Maturity, within One Year, Weighted Average Yield |
| us-gaap:DebtSecuritiesAvailableForSaleMaturityWithinOneYearWeightedAverageYield |
| Weighted average yield of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), maturing in next fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date. |
| cm:Concept |
| Percent (num:percentItemType) |
| As Of (instant) |
| (no balance type) |
| false |
| us-gaap:DebtSecuritiesAvailableForSaleMaturityWithinOneYearWeightedAverageYield |