 | us-gaap:InventoryGasInStorageUndergroundNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified |
 | us-gaap:InventoryDrillingNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified |
 | us-gaap:OtherInventoryNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified |
 | us-gaap:InventoryNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified |
 | us-gaap:InventoryGasInStorageUndergroundNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassifiedStatementTable |
 | us-gaap:InventoryDrillingNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassifiedStatementTable |
 | us-gaap:OtherInventoryNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassifiedStatementTable |
 | us-gaap:InventoryNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassifiedStatementTable |
 | us-gaap:InventoryDrillingNoncurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:InventoryGasInStorageUndergroundNoncurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:OtherInventoryNoncurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |
 | us-gaap:InventoryNoncurrent | parent-child | http://fasb.org/us-gaap/role/disclosure/Inventory |