v3.26.1
Transactions with related parties (Details) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Pension funds      
Transactions With Related Parties      
Payables and other liabilities € 3    
Costs 25    
Supplementary Healthcare Fund for Managers of Eni Group Companies (FISDE)      
Transactions With Related Parties      
Payables and other liabilities 1    
Costs 5    
Eni Enrico Mattei Foundation      
Transactions With Related Parties      
Costs 4    
Eni Foundation      
Transactions With Related Parties      
Revenues 1    
Costs 5    
Transactions and balances      
Transactions With Related Parties      
Receivables and other assets 1,658 € 1,797 € 1,563
Payables and other liabilities 4,831 4,571 4,818
Guarantees 8,296 7,893 8,041
Revenues 3,258 3,276 4,478
Costs 17,753 17,403 15,888
Other operating (expense) income (264) 201 17
Individual amount limit to be included in other related parties 50 50 50
Transactions and balances | Joint ventures and associates and investments in unconsolidated entities controlled by Eni      
Transactions With Related Parties      
Receivables and other assets 1,019 906 663
Payables and other liabilities 3,655 3,160 3,554
Guarantees 8,296 7,893 8,041
Revenues 467 472 383
Costs 12,240 12,052 10,882
Other operating (expense) income (554) (195) (165)
Transactions and balances | Joint ventures and associates      
Transactions With Related Parties      
Receivables and other assets 830 729 498
Payables and other liabilities 3,644 3,150 3,540
Guarantees 8,163 7,687 7,845
Revenues 437 435 358
Costs 12,226 12,034 10,852
Other operating (expense) income (554) (195) (165)
Transactions and balances | Agiba Petroleum Co      
Transactions With Related Parties      
Receivables and other assets 3 4 1
Payables and other liabilities 135 126 194
Revenues 1    
Costs 333 256 308
Transactions and balances | Cardon IV SA      
Transactions With Related Parties      
Receivables and other assets 1 1 24
Payables and other liabilities 134 77 142
Revenues   4 4
Costs   (2) 1
Transactions and balances | Coral FLNG SA      
Transactions With Related Parties      
Receivables and other assets 12 12 4
Guarantees 1,247 1,411 1,327
Revenues 21 15 6
Costs   (3)  
Transactions and balances | Eni CCUS Holding      
Transactions With Related Parties      
Receivables and other assets 118    
Guarantees 1,218    
Transactions and balances | Azule Group      
Transactions With Related Parties      
Receivables and other assets 119 59 113
Payables and other liabilities 361 399 475
Guarantees 2,939 3,343 3,156
Revenues 93 76 86
Costs 1,643 2,290 2,146
Transactions and balances | Saipem Group      
Transactions With Related Parties      
Receivables and other assets 41 41 5
Payables and other liabilities 136 186 235
Guarantees 9 9 9
Revenues 9 52 6
Costs 536 1,253 768
Transactions and balances | SeaCorridor Group      
Transactions With Related Parties      
Receivables and other assets 67 105 29
Payables and other liabilities 19 27 29
Revenues 2 1 1
Costs 266 242 357
Transactions and balances | Vårgrønn Group      
Transactions With Related Parties      
Receivables and other assets 1 1  
Guarantees 678 886 1,321
Revenues 1    
Transactions and balances | In Salah Gas Ltd      
Transactions With Related Parties      
Payables and other liabilities 57    
Costs 279    
Transactions and balances | Ithaca Energy Plc      
Transactions With Related Parties      
Receivables and other assets 146 188  
Payables and other liabilities 73 76  
Revenues 12    
Costs 535 366  
Other operating (expense) income (553) (138)  
Transactions and balances | Karachaganak Petroleum Operating BV      
Transactions With Related Parties      
Receivables and other assets 27 31 17
Payables and other liabilities 119 292 250
Revenues 2    
Costs 992 1,198 1,183
Transactions and balances | Lotte Versalis Elastomers Co Ltd      
Transactions With Related Parties      
Receivables and other assets 8 6  
Payables and other liabilities 13 14  
Revenues 3 3  
Costs 61 51  
Transactions and balances | Mellitah Oil & Gas BV      
Transactions With Related Parties      
Receivables and other assets 56 56 49
Payables and other liabilities 241 52 20
Revenues 10 11 16
Costs 1,031 523 517
Transactions and balances | Mozambique Rovuma Venture SpA      
Transactions With Related Parties      
Receivables and other assets   26  
Payables and other liabilities   2  
Revenues   31  
Costs   53  
Transactions and balances | Petrobel Belayim Petroleum Co      
Transactions With Related Parties      
Receivables and other assets 13 23 58
Payables and other liabilities 470 509 885
Revenues 5    
Costs 778 562 870
Transactions and balances | Societe Centrale Electrique du Congo SA      
Transactions With Related Parties      
Receivables and other assets 91 97 74
Revenues 79 104 79
Transactions and balances | Societa Oleodotti Meridionali SpA      
Transactions With Related Parties      
Receivables and other assets 22 12 11
Payables and other liabilities 500 491 473
Revenues 25 16 19
Costs 16 11 12
Transactions and balances | St. Bernard Renewables Llc [member]      
Transactions With Related Parties      
Receivables and other assets 1    
Guarantees 98    
Revenues 1    
Costs 9    
Transactions and balances | Var Energi ASA      
Transactions With Related Parties      
Receivables and other assets 26 30 51
Payables and other liabilities 1,321 828 764
Guarantees 1,948 1,918 2,013
Revenues 61 48 58
Costs 5,523 5,047 4,487
Other operating (expense) income (1) (57) (165)
Transactions and balances | Other joint ventures and associates      
Transactions With Related Parties      
Receivables and other assets 78 37 62
Payables and other liabilities 65 71 73
Guarantees 26 120 19
Revenues 108 74 83
Costs 224 187 203
Transactions and balances | Investments in unconsolidated entities controlled by Eni      
Transactions With Related Parties      
Receivables and other assets 189 177 165
Payables and other liabilities 11 10 14
Guarantees 133 206 196
Revenues 30 37 25
Costs 14 18 30
Transactions and balances | Eni BTC Ltd      
Transactions With Related Parties      
Guarantees   195 183
Transactions and balances | Industria Siciliana Acido Fosforico ISAF SPA      
Transactions With Related Parties      
Receivables and other assets 170 161 152
Payables and other liabilities 1 3 4
Guarantees     1
Revenues 9 10 12
Transactions and balances | VME Oilfield Chemicals Llc [Member]      
Transactions With Related Parties      
Guarantees 112    
Transactions and balances | Other unconsolidated subsidiaries      
Transactions With Related Parties      
Receivables and other assets 19 16 13
Payables and other liabilities 10 7 10
Guarantees 21 11 12
Revenues 21 27 13
Costs 14 18 30
Transactions and balances | Entities controlled by the Government      
Transactions With Related Parties      
Receivables and other assets 423 574 677
Payables and other liabilities 865 1,092 1,050
Revenues 2,738 2,770 4,054
Costs 4,745 4,715 4,401
Other operating (expense) income 290 396 182
Transactions and balances | Cassa Depositi e Prestiti Group      
Transactions With Related Parties      
Receivables and other assets 22 3 5
Payables and other liabilities 19 25 33
Revenues     2
Costs 87 65 69
Transactions and balances | Enel Group      
Transactions With Related Parties      
Receivables and other assets 89 33 95
Payables and other liabilities 183 153 168
Revenues 45 46 93
Costs 650 798 497
Other operating (expense) income 66 (28) (109)
Transactions and balances | Italgas Group      
Transactions With Related Parties      
Receivables and other assets 2 1 1
Payables and other liabilities 190 186 149
Revenues 7 5 8
Costs 718 612 (20)
Transactions and balances | Snam Group      
Transactions With Related Parties      
Receivables and other assets 110   245
Payables and other liabilities 247 436 352
Revenues 77 219 1,157
Costs 1,086 1,342 1,625
Transactions and balances | Terna Group      
Transactions With Related Parties      
Receivables and other assets 62 104 85
Payables and other liabilities 75 116 61
Revenues 266 386 400
Costs 343 350 317
Other operating (expense) income 5 10 8
Transactions and balances | GSE - Gestore Servizi Energetici      
Transactions With Related Parties      
Receivables and other assets 112 201 230
Payables and other liabilities 100 110 219
Revenues 2,147 1,805 2,104
Costs 1,861 1,548 1,875
Other operating (expense) income 219 414 283
Transactions and balances | ITA Airways - Italia Trasporto Aereo SpA      
Transactions With Related Parties      
Receivables and other assets 3 13 5
Revenues 99 238 238
Transactions and balances | Other entities controlled by government      
Transactions With Related Parties      
Receivables and other assets 23 23 11
Payables and other liabilities 51 66 68
Revenues 97 71 52
Costs     38
Transactions and balances | Other related parties      
Transactions With Related Parties      
Receivables and other assets   1 1
Payables and other liabilities 4 3 2
Revenues 1 2 1
Costs 39 37 36
Transactions and balances | Groupement Sonatrach – Eni «GSE»      
Transactions With Related Parties      
Receivables and other assets 216 316 222
Payables and other liabilities 307 316 212
Revenues 52 32 40
Costs € 729 € 599 € 569