v3.26.1
Transactions with related parties - Financing transactions with related parties (Details) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Transactions With Related Parties      
Finance incomes and derivative financial instruments € 7,196 € 7,715 € 7,417
Finance Expenses 8,170 8,980 8,113
Gain on disposals 426 984 1,108
Financing transactions      
Transactions With Related Parties      
Receivables and cash and cash equivalents 2,969 2,428 1,862
Payables 593 419 335
Guarantees 4 1,541 1,449
Finance incomes and derivative financial instruments 215 198 156
Finance Expenses 77 57 28
Gain on disposals (18) (12) 445
Individual amount limit to be included in other related parties 50    
Financing transactions | Joint ventures and associates      
Transactions With Related Parties      
Receivables and cash and cash equivalents 2,928 2,388 1,841
Payables 451 319 239
Guarantees 4 1,541 1,449
Finance incomes and derivative financial instruments 212 195 155
Finance Expenses 71 51 22
Gain on disposals     1
Financing transactions | Coral FLNG SA      
Transactions With Related Parties      
Receivables and cash and cash equivalents 417 522 453
Finance incomes and derivative financial instruments 20 24 15
Financing transactions | Eni CCUS Holding      
Transactions With Related Parties      
Receivables and cash and cash equivalents 123    
Financing transactions | Coral South FLNG DMCC      
Transactions With Related Parties      
Guarantees   1,539 1,448
Finance Expenses   (1)  
Financing transactions | E&E Algeria Touat BV      
Transactions With Related Parties      
Payables 56    
Financing transactions | Saipem Group      
Transactions With Related Parties      
Payables 247 222 56
Finance incomes and derivative financial instruments   1  
Finance Expenses 11   8
Financing transactions | Mozambique Rovuma Venture SpA      
Transactions With Related Parties      
Receivables and cash and cash equivalents 2,318 1,769 1,339
Payables 91 58 170
Finance incomes and derivative financial instruments 147 132 101
Finance Expenses 11 11  
Financing transactions | Pengerang Biorefinery SDN BHD [Member]      
Transactions With Related Parties      
Receivables and cash and cash equivalents   60  
Financing transactions | Other joint ventures and associates      
Transactions With Related Parties      
Receivables and cash and cash equivalents 70 37 49
Payables 57 39 13
Guarantees 4 2 1
Finance incomes and derivative financial instruments 45 38 39
Finance Expenses 49 41 14
Gain on disposals     1
Financing transactions | Investments in unconsolidated entities controlled by Eni      
Transactions With Related Parties      
Receivables and cash and cash equivalents 41 40 7
Payables 55 36 38
Finance incomes and derivative financial instruments 2 2 1
Finance Expenses 1 2 1
Financing transactions | Other unconsolidated subsidiaries      
Transactions With Related Parties      
Receivables and cash and cash equivalents 41 40 7
Payables 55 36 38
Finance incomes and derivative financial instruments 2 2 1
Finance Expenses 1 2 1
Financing transactions | Entities controlled by the Government      
Transactions With Related Parties      
Receivables and cash and cash equivalents     14
Payables 87 60 58
Finance incomes and derivative financial instruments 1 1  
Finance Expenses 5 4 5
Gain on disposals (18) (12) 444
Financing transactions | Cassa Depositi e Prestiti Group      
Transactions With Related Parties      
Payables 52 53 56
Finance Expenses 2   2
Financing transactions | Snam Group      
Transactions With Related Parties      
Gain on disposals     443
Financing transactions | Other entities controlled by government      
Transactions With Related Parties      
Receivables and cash and cash equivalents     14
Payables 35 7 2
Finance incomes and derivative financial instruments 1 1  
Finance Expenses 3 4 3
Gain on disposals € (18) (12) € 1
Financing transactions | Other related parties      
Transactions With Related Parties      
Payables   € 4