| Standard label: | Oil and Gas Delivery Commitments and Contracts [Axis] |
| Name: | us-gaap:OilAndGasDeliveryCommitmentsAndContractsAxis |
| Documentation: | This element represents the categories used to group oil and gas delivery commitments and contracts. |
| Object type: | cm:Axis |
| Data type: | Text/String (xbrli:stringItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | true |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:OilAndGasDeliveryCommitmentsAndContractsAxis |
| Label | Role | Language |
| Oil and Gas Delivery Commitments and Contracts [Axis] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| SEC Regulation S-K (SK) 229 1207 | http://fasb.org/us-gaap/role/ref/legacyRef | 932 |