 | us-gaap:DerivativeAssetsNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified-RealEstateOperations |
 | us-gaap:HedgingAssetsNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified-RealEstateOperations |
 | us-gaap:DerivativeInstrumentsAndHedgesNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified-RealEstateOperations |
 | us-gaap:DerivativeAssetsNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified-RealEstateOperationsStatementTable |
 | us-gaap:HedgingAssetsNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified-RealEstateOperationsStatementTable |
 | us-gaap:DerivativeInstrumentsAndHedgesNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified-RealEstateOperationsStatementTable |
 | us-gaap:DerivativeAssetsNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified |
 | us-gaap:HedgingAssetsNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified |
 | us-gaap:CommodityContractAssetNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified |
 | us-gaap:EnergyMarketingContractsAssetsNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified |
 | us-gaap:DerivativeInstrumentsAndHedgesNoncurrent | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassified |
 | us-gaap:DerivativeAssetsNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassifiedStatementTable |
 | us-gaap:HedgingAssetsNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassifiedStatementTable |
 | us-gaap:CommodityContractAssetNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassifiedStatementTable |
 | us-gaap:EnergyMarketingContractsAssetsNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassifiedStatementTable |
 | us-gaap:DerivativeInstrumentsAndHedgesNoncurrent | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfFinancialPositionClassifiedStatementTable |