 | us-gaap:EnergyRelatedInventoryPetroleum | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:EnergyRelatedInventoryNaturalGasLiquids | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:EnergyRelatedInventoryNaturalGasInStorage | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:EnergyRelatedInventoryGasStoredUnderground | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:EnergyRelatedInventoryPropaneGas | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:EnergyRelatedInventoryCoal | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:EnergyRelatedInventoryChemicals | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:EnergyRelatedInventoryOtherFossilFuel | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:CrudeOilAndNaturalGasLiquids | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:InventoryCrudeOilProductsAndMerchandise | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:EnergyRelatedInventory | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:EnergyRelatedInventoryPetroleum | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:EnergyRelatedInventoryNaturalGasLiquids | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:EnergyRelatedInventoryNaturalGasInStorage | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:EnergyRelatedInventoryGasStoredUnderground | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:EnergyRelatedInventoryPropaneGas | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:EnergyRelatedInventoryCoal | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:EnergyRelatedInventoryChemicals | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:EnergyRelatedInventoryOtherFossilFuel | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:CrudeOilAndNaturalGasLiquids | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:InventoryCrudeOilProductsAndMerchandise | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |
 | us-gaap:EnergyRelatedInventory | domain-member | http://fasb.org/us-gaap/role/disclosure/InventoryInventoryCurrentTable |