cm:Concept: us-gaap:LongTermPurchaseCommitmentMinimumEnergyVolumeRequired
| Long-term Purchase Commitment, Minimum Energy Volume Required |
| us-gaap:LongTermPurchaseCommitmentMinimumEnergyVolumeRequired |
| Energy volume that must be purchased within the specified time period of the agreement to avoid penalties or unfavorable effects on pricing, among other adverse consequences. |
| cm:Concept |
| num:energyItemType |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:LongTermPurchaseCommitmentMinimumEnergyVolumeRequired |