{
 "documentInfo": {
  "documentType": "https://xbrl.org/CR/2021-02-03/xbrl-json",
  "features": {
   "xbrl:canonicalValues": true
  },
  "namespaces": {
   "bsycx13y0notv14v9n85": "http://repsol.com/xbrl/2020",
   "ifrs-full": "http://xbrl.ifrs.org/taxonomy/2020-03-16/ifrs-full",
   "iso4217": "http://www.xbrl.org/2003/iso4217",
   "scheme": "http://standards.iso.org/iso/17442",
   "xbrl": "https://xbrl.org/CR/2021-02-03",
   "xbrli": "http://www.xbrl.org/2003/instance"
  },
  "taxonomy": [
   "http://repsol.com/xbrl/2020/bsycx13y0notv14v9n85-2020-12-31.xsd"
  ]
 },
 "facts": {
  "fact-10": {
   "value": "3353000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IntangibleAssetsAndGoodwill",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-11": {
   "value": "4470000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IntangibleAssetsAndGoodwill",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-12": {
   "value": "20927000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:PropertyPlantAndEquipment",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-13": {
   "value": "23145000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:PropertyPlantAndEquipment",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-14": {
   "value": "5897000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:InvestmentAccountedForUsingEquityMethod",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-15": {
   "value": "7237000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:InvestmentAccountedForUsingEquityMethod",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-16": {
   "value": "916000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentFinancialAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-17": {
   "value": "1125000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentFinancialAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-18": {
   "value": "3745000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DeferredTaxAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-19": {
   "value": "4050000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DeferredTaxAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-20": {
   "value": "880000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherNoncurrentNonfinancialAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-21": {
   "value": "1381000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherNoncurrentNonfinancialAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-22": {
   "value": "35718000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-23": {
   "value": "41408000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-24": {
   "value": "5000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-25": {
   "value": "5000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentAssetsOrDisposalGroupsClassifiedAsHeldForSaleOrAsHeldForDistributionToOwners",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-26": {
   "value": "3379000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Inventories",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-27": {
   "value": "4597000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Inventories",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-28": {
   "value": "4056000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:TradeAndOtherCurrentReceivables",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-29": {
   "value": "5911000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:TradeAndOtherCurrentReceivables",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-30": {
   "value": "239000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherCurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-31": {
   "value": "195000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherCurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-32": {
   "value": "1584000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherCurrentFinancialAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-33": {
   "value": "2800000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherCurrentFinancialAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-34": {
   "value": "4321000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-35": {
   "value": "2979000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-36": {
   "value": "13584000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-37": {
   "value": "16487000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-38": {
   "value": "49302000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Assets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-39": {
   "value": "57895000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Assets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-40": {
   "value": "21185000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolFondosPropios",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-41": {
   "value": "24335000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolFondosPropios",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-42": {
   "value": "-890000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:AccumulatedOtherComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-43": {
   "value": "593000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:AccumulatedOtherComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-44": {
   "value": "244000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncontrollingInterests",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-45": {
   "value": "281000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncontrollingInterests",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-46": {
   "value": "20539000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-47": {
   "value": "25209000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-48": {
   "value": "3572000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentProvisions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-49": {
   "value": "3912000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentProvisions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-50": {
   "value": "12123000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentFinancialLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-51": {
   "value": "10929000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentFinancialLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-52": {
   "value": "2142000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DeferredTaxLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-53": {
   "value": "2375000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DeferredTaxLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-54": {
   "value": "407000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherNoncurrentLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-55": {
   "value": "385000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherNoncurrentLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-56": {
   "value": "18244000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-57": {
   "value": "17601000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:NoncurrentLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-58": {
   "value": "740000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CurrentProvisions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-59": {
   "value": "865000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CurrentProvisions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-60": {
   "value": "3880000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CurrentFinancialLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-61": {
   "value": "6538000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CurrentFinancialLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-62": {
   "value": "5899000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:TradeAndOtherCurrentPayables",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-63": {
   "value": "7682000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:TradeAndOtherCurrentPayables",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-64": {
   "value": "10519000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CurrentLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-65": {
   "value": "15085000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CurrentLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-66": {
   "value": "49302000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:EquityAndLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-67": {
   "value": "57895000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:EquityAndLiabilities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-68": {
   "value": "32956000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:RevenueFromSaleOfGoods",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-69": {
   "value": "49006000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:RevenueFromSaleOfGoods",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-70": {
   "value": "326000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:RevenueFromRenderingOfServices",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-71": {
   "value": "322000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:RevenueFromRenderingOfServices",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-72": {
   "value": "624000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ChangesInInventoriesOfFinishedGoodsAndWorkInProgress",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-73": {
   "value": "-11000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ChangesInInventoriesOfFinishedGoodsAndWorkInProgress",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-74": {
   "value": "985000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-75": {
   "value": "725000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-76": {
   "value": "24835000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:RawMaterialsAndConsumablesUsed",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-77": {
   "value": "36803000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:RawMaterialsAndConsumablesUsed",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-78": {
   "value": "2207000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DepreciationAndAmortisationExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-79": {
   "value": "2434000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DepreciationAndAmortisationExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-80": {
   "value": "2159000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-81": {
   "value": "5322000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-82": {
   "value": "1845000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:EmployeeBenefitsExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-83": {
   "value": "1946000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:EmployeeBenefitsExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-84": {
   "value": "1272000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:TransportationExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-85": {
   "value": "1314000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:TransportationExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-86": {
   "value": "-556000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolSuministros",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-87": {
   "value": "-888000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolSuministros",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-88": {
   "value": "102000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnDisposalsOfNoncurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-89": {
   "value": "147000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnDisposalsOfNoncurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-90": {
   "value": "3425000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:MiscellaneousOtherOperatingExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-91": {
   "value": "4755000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:MiscellaneousOtherOperatingExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-92": {
   "value": "-2554000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossFromOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-93": {
   "value": "-3251000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossFromOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-94": {
   "value": "-244000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:InterestRevenueExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-95": {
   "value": "-243000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:InterestRevenueExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-96": {
   "value": "-148000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnChangeInFairValueOfDerivatives",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-97": {
   "value": "216000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnChangeInFairValueOfDerivatives",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-98": {
   "value": "406000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnExchangeDifferencesOnTranslationRecognisedInProfitOrLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-99": {
   "value": "-27000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnExchangeDifferencesOnTranslationRecognisedInProfitOrLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-100": {
   "value": "-57000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ImpairmentLossOnFinancialAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-101": {
   "value": "-6000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ImpairmentLossOnFinancialAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-102": {
   "value": "-212000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherFinanceIncomeCost",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-103": {
   "value": "-253000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherFinanceIncomeCost",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-104": {
   "value": "-141000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:FinanceIncomeCost",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-105": {
   "value": "-301000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:FinanceIncomeCost",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-106": {
   "value": "-609000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ShareOfProfitLossOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-107": {
   "value": "351000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ShareOfProfitLossOfAssociatesAndJointVenturesAccountedForUsingEquityMethod",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-108": {
   "value": "-3304000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-109": {
   "value": "-3201000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-110": {
   "value": "16000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncomeTaxExpenseContinuingOperations",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-111": {
   "value": "588000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncomeTaxExpenseContinuingOperations",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-112": {
   "value": "-3320000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-113": {
   "value": "-3789000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-114": {
   "value": "31000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossFromContinuingOperationsAttributableToNoncontrollingInterests",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-115": {
   "value": "-27000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossFromContinuingOperationsAttributableToNoncontrollingInterests",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-116": {
   "value": "-3289000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossAttributableToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-117": {
   "value": "-3816000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossAttributableToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-118": {
   "value": "-2.13",
   "decimals": 4,
   "dimensions": {
    "concept": "ifrs-full:BasicEarningsLossPerShare",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR/xbrli:shares"
   }
  },
  "fact-119": {
   "value": "-2.33",
   "decimals": 4,
   "dimensions": {
    "concept": "ifrs-full:BasicEarningsLossPerShare",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR/xbrli:shares"
   }
  },
  "fact-120": {
   "value": "-2.13",
   "decimals": 4,
   "dimensions": {
    "concept": "ifrs-full:DilutedEarningsLossPerShare",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR/xbrli:shares"
   }
  },
  "fact-121": {
   "value": "-2.33",
   "decimals": 4,
   "dimensions": {
    "concept": "ifrs-full:DilutedEarningsLossPerShare",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR/xbrli:shares"
   }
  },
  "fact-122": {
   "value": "-3320000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-123": {
   "value": "-3789000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-124": {
   "value": "-9000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-125": {
   "value": "-5000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeBeforeTaxGainsLossesOnRemeasurementsOfDefinedBenefitPlans",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-126": {
   "value": "-11000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ShareOfOtherComprehensiveIncomeOfAssociatesAndJointVenturesAccountedForUsingEquityMethodThatWillNotBeReclassifiedToProfitOrLossBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-127": {
   "value": "-3000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ShareOfOtherComprehensiveIncomeOfAssociatesAndJointVenturesAccountedForUsingEquityMethodThatWillNotBeReclassifiedToProfitOrLossBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-128": {
   "value": "-27000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeBeforeTaxGainsLossesFromInvestmentsInEquityInstruments",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-129": {
   "value": "14000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeBeforeTaxGainsLossesFromInvestmentsInEquityInstruments",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-130": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-131": {
   "value": "-1000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-132": {
   "value": "-47000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-133": {
   "value": "7000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeThatWillNotBeReclassifiedToProfitOrLossNetOfTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-134": {
   "value": "58000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeBeforeTaxCashFlowHedges",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-135": {
   "value": "1000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeBeforeTaxCashFlowHedges",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-136": {
   "value": "78000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnCashFlowHedgesBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-137": {
   "value": "-55000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnCashFlowHedgesBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-138": {
   "value": "20000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ReclassificationAdjustmentsOnCashFlowHedgesBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-139": {
   "value": "-56000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ReclassificationAdjustmentsOnCashFlowHedgesBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-140": {
   "value": "-1482000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeBeforeTaxExchangeDifferencesOnTranslation",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-141": {
   "value": "406000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeBeforeTaxExchangeDifferencesOnTranslation",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-142": {
   "value": "-1445000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnExchangeDifferencesOnTranslationBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-143": {
   "value": "431000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:GainsLossesOnExchangeDifferencesOnTranslationBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-144": {
   "value": "37000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-145": {
   "value": "25000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ReclassificationAdjustmentsOnExchangeDifferencesOnTranslationBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-146": {
   "value": "-35000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-147": {
   "value": "12000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncomeTaxRelatingToComponentsOfOtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-148": {
   "value": "-1459000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-149": {
   "value": "419000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncomeThatWillBeReclassifiedToProfitOrLossNetOfTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-150": {
   "value": "-1506000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-151": {
   "value": "426000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-152": {
   "value": "-4826000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-153": {
   "value": "-3363000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-154": {
   "value": "-4792000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncomeAttributableToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-155": {
   "value": "-3391000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncomeAttributableToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-156": {
   "value": "-34000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncomeAttributableToNoncontrollingInterests",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-157": {
   "value": "28000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncomeAttributableToNoncontrollingInterests",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-158": {
   "value": "1559000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-159": {
   "value": "25894000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-160": {
   "value": "-350000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-161": {
   "value": "2341000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-162": {
   "value": "1024000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-163": {
   "value": "160000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-164": {
   "value": "286000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-165": {
   "value": "30914000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-166": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolImpactoPrimeraAplicacionNuevasNormas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2018-12-31T00:00:00/2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-167": {
   "value": "-162000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolImpactoPrimeraAplicacionNuevasNormas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2018-12-31T00:00:00/2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-168": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolImpactoPrimeraAplicacionNuevasNormas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2018-12-31T00:00:00/2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-169": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolImpactoPrimeraAplicacionNuevasNormas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2018-12-31T00:00:00/2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-170": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolImpactoPrimeraAplicacionNuevasNormas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2018-12-31T00:00:00/2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-171": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolImpactoPrimeraAplicacionNuevasNormas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2018-12-31T00:00:00/2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-172": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolImpactoPrimeraAplicacionNuevasNormas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2018-12-31T00:00:00/2019-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-173": {
   "value": "-162000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolImpactoPrimeraAplicacionNuevasNormas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2018-12-31T00:00:00/2019-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-174": {
   "value": "1559000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-175": {
   "value": "25732000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-176": {
   "value": "-350000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-177": {
   "value": "2341000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-178": {
   "value": "1024000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-179": {
   "value": "160000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-180": {
   "value": "286000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-181": {
   "value": "30752000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-02T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-182": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-183": {
   "value": "-7000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-184": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-185": {
   "value": "-3816000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-186": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-187": {
   "value": "432000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-188": {
   "value": "28000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2019-01-02T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-189": {
   "value": "-3363000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2019-01-02T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-190": {
   "value": "78000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-191": {
   "value": "-78000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-192": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-193": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-194": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-195": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-196": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-197": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-198": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-199": {
   "value": "-330000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-200": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-201": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-202": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-203": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-204": {
   "value": "-7000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-205": {
   "value": "-337000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-206": {
   "value": "-71000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-207": {
   "value": "-932000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-208": {
   "value": "-820000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-209": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-210": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-211": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-212": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-213": {
   "value": "-1823000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-214": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughDisposalOfSubsidiary",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-215": {
   "value": "21000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughDisposalOfSubsidiary",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-216": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughDisposalOfSubsidiary",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-217": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughDisposalOfSubsidiary",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-218": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughDisposalOfSubsidiary",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-219": {
   "value": "4000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughDisposalOfSubsidiary",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-220": {
   "value": "-25000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughDisposalOfSubsidiary",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-221": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughDisposalOfSubsidiary",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-222": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-223": {
   "value": "2341000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-224": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-225": {
   "value": "-2341000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-226": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-227": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-228": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-229": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-230": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-231": {
   "value": "-29000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-232": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-233": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-234": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-235": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-236": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-237": {
   "value": "-29000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-238": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-239": {
   "value": "13000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-240": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-241": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-242": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-243": {
   "value": "-3000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-244": {
   "value": "-1000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-245": {
   "value": "9000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-246": {
   "value": "1566000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-247": {
   "value": "26731000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-248": {
   "value": "-1170000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-249": {
   "value": "-3816000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-250": {
   "value": "1024000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-251": {
   "value": "593000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-252": {
   "value": "281000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-253": {
   "value": "25209000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-254": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-255": {
   "value": "-20000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-256": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-257": {
   "value": "-3289000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-258": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-259": {
   "value": "-1483000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-260": {
   "value": "-34000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-261": {
   "value": "-4826000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ComprehensiveIncome",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-262": {
   "value": "101000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-263": {
   "value": "-101000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-264": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-265": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-266": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-267": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-268": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-269": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolAmpliacionReduccionDeCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-270": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-271": {
   "value": "-338000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-272": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-273": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-274": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-275": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-276": {
   "value": "-1000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-277": {
   "value": "-339000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsRecognisedAsDistributionsToOwnersOfParent",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-278": {
   "value": "-99000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-279": {
   "value": "-1267000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-280": {
   "value": "1008000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-281": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-282": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-283": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-284": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-285": {
   "value": "-358000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTreasuryShareTransactions",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-286": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-287": {
   "value": "-3816000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-288": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-289": {
   "value": "3816000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-290": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-291": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-292": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-293": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolTransferenciasEntrePartidasDePatrimonioNeto",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-294": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-295": {
   "value": "-54000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-296": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-297": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-298": {
   "value": "907000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-299": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-300": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-301": {
   "value": "853000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolObligacionesPerpetuasSubordinadas",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-302": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-303": {
   "value": "-3000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-304": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-305": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-306": {
   "value": "5000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-307": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-308": {
   "value": "-2000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-309": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseThroughTransfersAndOtherChangesEquity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-310": {
   "value": "1568000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:IssuedCapitalMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-311": {
   "value": "21132000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolPrimaDeEmisionYReservasMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-312": {
   "value": "-162000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:TreasurySharesMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-313": {
   "value": "-3289000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolResultadoDelEjercicioAtribuidoALaEntidadDominanteMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-314": {
   "value": "1936000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "bsycx13y0notv14v9n85:RepsolOtrosInstrumentosDePatrimonioMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-315": {
   "value": "-890000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:AccumulatedOtherComprehensiveIncomeMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-316": {
   "value": "244000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "ifrs-full:ComponentsOfEquityAxis": "ifrs-full:NoncontrollingInterestsMember",
    "unit": "iso4217:EUR"
   }
  },
  "fact-317": {
   "value": "20539000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Equity",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-318": {
   "value": "-3304000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-319": {
   "value": "-3201000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProfitLossBeforeTax",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-320": {
   "value": "5074000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:AdjustmentsForReconcileProfitLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-321": {
   "value": "8632000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:AdjustmentsForReconcileProfitLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-322": {
   "value": "2207000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:AdjustmentsForDepreciationAndAmortisationExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-323": {
   "value": "2434000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:AdjustmentsForDepreciationAndAmortisationExpense",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-324": {
   "value": "2867000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherAdjustmentsToReconcileProfitLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-325": {
   "value": "6198000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherAdjustmentsToReconcileProfitLoss",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-326": {
   "value": "1000000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseInWorkingCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-327": {
   "value": "137000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseInWorkingCapital",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-328": {
   "value": "-32000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolOtrosFlujosDeEfectivoDeLasActividadesDeExplotacion",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-329": {
   "value": "-719000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolOtrosFlujosDeEfectivoDeLasActividadesDeExplotacion",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-330": {
   "value": "-183000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsReceivedClassifiedAsOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-331": {
   "value": "-464000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:DividendsReceivedClassifiedAsOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-332": {
   "value": "100000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncomeTaxesPaidClassifiedAsOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-333": {
   "value": "-975000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncomeTaxesPaidClassifiedAsOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-334": {
   "value": "315000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherInflowsOutflowsOfCashClassifiedAsOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-335": {
   "value": "208000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherInflowsOutflowsOfCashClassifiedAsOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-336": {
   "value": "2738000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashFlowsFromUsedInOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-337": {
   "value": "4849000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashFlowsFromUsedInOperatingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-338": {
   "value": "3368000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagoPorInversiones",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-339": {
   "value": "6390000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagoPorInversiones",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-340": {
   "value": "-132000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagoPorInversionesEnEmpresasDelGrupoAsociadasYUnidadesDeNegocio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-341": {
   "value": "-107000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagoPorInversionesEnEmpresasDelGrupoAsociadasYUnidadesDeNegocio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-342": {
   "value": "-1886000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:PurchaseOfPropertyPlantAndEquipmentIntangibleAssetsOtherThanGoodwillInvestmentPropertyAndOtherNoncurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-343": {
   "value": "-3227000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:PurchaseOfPropertyPlantAndEquipmentIntangibleAssetsOtherThanGoodwillInvestmentPropertyAndOtherNoncurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-344": {
   "value": "-1350000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:PurchaseOfFinancialInstrumentsClassifiedAsInvestingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-345": {
   "value": "-3056000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:PurchaseOfFinancialInstrumentsClassifiedAsInvestingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-346": {
   "value": "-3538000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobroPorDesinversiones",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-347": {
   "value": "-1895000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobroPorDesinversiones",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-348": {
   "value": "1010000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobroPorDesinversionesEnEmpresasDelGrupoAsociadasYUnidadesDeNegocio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-349": {
   "value": "17000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobroPorDesinversionesEnEmpresasDelGrupoAsociadasYUnidadesDeNegocio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-350": {
   "value": "104000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProceedsFromDisposalsOfPropertyPlantAndEquipmentIntangibleAssetsOtherThanGoodwillInvestmentPropertyAndOtherNoncurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-351": {
   "value": "133000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProceedsFromDisposalsOfPropertyPlantAndEquipmentIntangibleAssetsOtherThanGoodwillInvestmentPropertyAndOtherNoncurrentAssets",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-352": {
   "value": "2424000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProceedsFromSalesOrMaturityOfFinancialInstrumentsClassifiedAsInvestingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-353": {
   "value": "1745000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:ProceedsFromSalesOrMaturityOfFinancialInstrumentsClassifiedAsInvestingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-354": {
   "value": "52000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherInflowsOutflowsOfCashClassifiedAsInvestingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-355": {
   "value": "88000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherInflowsOutflowsOfCashClassifiedAsInvestingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-356": {
   "value": "222000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashFlowsFromUsedInInvestingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-357": {
   "value": "-4407000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashFlowsFromUsedInInvestingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-358": {
   "value": "-508000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobrosPagosPorInstrumentosDePatrimonio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-359": {
   "value": "1844000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobrosPagosPorInstrumentosDePatrimonio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-360": {
   "value": "1491000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolEmision",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-361": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolEmision",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-362": {
   "value": "-605000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolDevolucionYAmortizacion",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-363": {
   "value": "0",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolDevolucionYAmortizacion",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-364": {
   "value": "-766000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobrosPorInstrumentosDePatrimonio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-365": {
   "value": "-1911000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobrosPorInstrumentosDePatrimonio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-366": {
   "value": "388000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagosPorInstrumentosDePatrimonio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-367": {
   "value": "67000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagosPorInstrumentosDePatrimonio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-368": {
   "value": "1206000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobrosPagosPorInstrumentosDePasivoFinanciero",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-369": {
   "value": "-412000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobrosPagosPorInstrumentosDePasivoFinanciero",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-370": {
   "value": "10163000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobrosPorLaEmisionDePasivosFinancieros",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-371": {
   "value": "13213000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolCobrosPorLaEmisionDePasivosFinancieros",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-372": {
   "value": "-11369000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagosPorLaDevolucionYAmortizacionDePasivosFinancieros",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-373": {
   "value": "-12801000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagosPorLaDevolucionYAmortizacionDePasivosFinancieros",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-374": {
   "value": "346000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagosPorRemuneracionesDeAccionistasYOtrosInstrumentosDePatrimonio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-375": {
   "value": "396000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolPagosPorRemuneracionesDeAccionistasYOtrosInstrumentosDePatrimonio",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-376": {
   "value": "571000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolOtrosFlujosDeEfectivoDeActividadesDeFinanciacion",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-377": {
   "value": "461000000",
   "decimals": -6,
   "dimensions": {
    "concept": "bsycx13y0notv14v9n85:RepsolOtrosFlujosDeEfectivoDeActividadesDeFinanciacion",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-378": {
   "value": "-417000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:InterestPaidClassifiedAsFinancingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-379": {
   "value": "-467000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:InterestPaidClassifiedAsFinancingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-380": {
   "value": "-154000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherInflowsOutflowsOfCashClassifiedAsFinancingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-381": {
   "value": "6000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:OtherInflowsOutflowsOfCashClassifiedAsFinancingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-382": {
   "value": "-1615000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashFlowsFromUsedInFinancingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-383": {
   "value": "-2289000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashFlowsFromUsedInFinancingActivities",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-384": {
   "value": "-3000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:EffectOfExchangeRateChangesOnCashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-385": {
   "value": "40000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:EffectOfExchangeRateChangesOnCashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-386": {
   "value": "1342000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseInCashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-387": {
   "value": "-1807000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:IncreaseDecreaseInCashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-01T00:00:00/2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-388": {
   "value": "2979000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-02T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-389": {
   "value": "4786000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2019-01-02T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-390": {
   "value": "4321000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-391": {
   "value": "2979000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashAndCashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-392": {
   "value": "2234000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Cash",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-393": {
   "value": "2370000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:Cash",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-394": {
   "value": "2087000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2021-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-395": {
   "value": "609000000",
   "decimals": -6,
   "dimensions": {
    "concept": "ifrs-full:CashEquivalents",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00",
    "unit": "iso4217:EUR"
   }
  },
  "fact-1": {
   "value": "S.A.",
   "dimensions": {
    "concept": "ifrs-full:LegalFormOfEntity",
    "language": "es",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00"
   }
  },
  "fact-2": {
   "value": "Repsol,  S.A.",
   "dimensions": {
    "concept": "ifrs-full:NameOfUltimateParentOfGroup",
    "language": "es",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00"
   }
  },
  "fact-3": {
   "value": "realiza actividades en el sector de  hidrocarburos a lo  largo de  toda su cadena  de valor (exploraci\u00f3n,  desarrollo y  producci\u00f3n de crudo  y gas natural,  refino,  producci\u00f3n, transporte y comercializaci\u00f3n de una amplia gama de productos petrol\u00edferos, petroqu\u00edmicos y derivados y gas  natural), as\u00ed como actividades de generaci\u00f3n y comercializaci\u00f3n de energ\u00eda el\u00e9ctrica 2 .",
   "dimensions": {
    "concept": "ifrs-full:DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities",
    "language": "es",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00"
   }
  },
  "fact-4": {
   "value": "Espa\u00f1a",
   "dimensions": {
    "concept": "ifrs-full:CountryOfIncorporation",
    "language": "es",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00"
   }
  },
  "fact-5": {
   "value": "La entidad matriz del Grupo es Repsol, S.A.",
   "dimensions": {
    "concept": "ifrs-full:NameOfReportingEntityOrOtherMeansOfIdentification",
    "language": "es",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00"
   }
  },
  "fact-6": {
   "value": "calle M\u00e9ndez \u00c1lvaro n\u00famero 44 de Madrid",
   "dimensions": {
    "concept": "ifrs-full:AddressOfRegisteredOfficeOfEntity",
    "language": "es",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00"
   }
  },
  "fact-7": {
   "value": "Repsol, S.A.",
   "dimensions": {
    "concept": "ifrs-full:NameOfParentEntity",
    "language": "es",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00"
   }
  },
  "fact-8": {
   "value": "calle M\u00e9ndez \u00c1lvaro n\u00famero 44 de Madrid",
   "dimensions": {
    "concept": "ifrs-full:DomicileOfEntity",
    "language": "es",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00"
   }
  },
  "fact-9": {
   "value": "calle M\u00e9ndez \u00c1lvaro n\u00famero 44 de Madrid",
   "dimensions": {
    "concept": "ifrs-full:PrincipalPlaceOfBusiness",
    "language": "es",
    "entity": "scheme:BSYCX13Y0NOTV14V9N85",
    "period": "2020-01-01T00:00:00/2021-01-01T00:00:00"
   }
  }
 }
}