cm:Concept: us-gaap:IncreaseDecreaseInDeferredAirTrafficRevenue
| Increase (Decrease) in Deferred Air Traffic Revenue |
| us-gaap:IncreaseDecreaseInDeferredAirTrafficRevenue |
| The increase (decrease) during the reporting period in the amount of unearned revenue related to tickets sold but not yet recognized as revenue and the estimated incremental cost for points or miles outstanding and awards that expect to be redeemed through customer loyalty programs. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Debit |
| false |
| us-gaap:IncreaseDecreaseInDeferredAirTrafficRevenue |