v3.26.1
Right-of-use assets and lease liabilities (Details) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Right-of-use assets      
Net carrying amount - beginning of period € 5,822 € 4,834  
Additions 1,150 2,114  
Depreciation (1,244) (1,199) € (973)
Impairments (14) (40) (41)
Currency translation differences (386) 193  
Changes in the scope of consolidation   42  
Other changes (144) (122)  
Net carrying amount - end of period 5,184 5,822 4,834
Lessee's exposure arising from extension options related to service stations for sale of oil products € 153    
Ghana, Mexico and Ivory Coast [member] | Minimum      
Right-of-use assets      
Lease, term of contract 11 years    
Ghana, Mexico and Ivory Coast [member] | Maximum      
Right-of-use assets      
Lease, term of contract 15 years    
Exploration & Production      
Right-of-use assets      
Net carrying amount - beginning of period € 4,266    
Additions 860    
Net carrying amount - end of period 3,634 4,266  
Enilive, Refining and Chemicals [member]      
Right-of-use assets      
Net carrying amount - beginning of period 519    
Net carrying amount - end of period 538 519  
Corporate and Other activities      
Right-of-use assets      
Net carrying amount - beginning of period 476    
Net carrying amount - end of period 532 476  
Corporate and Other activities | Italy      
Right-of-use assets      
Additions 94    
Upstream business      
Right-of-use assets      
Lessee's exposure arising from other extension options related to ancillary assets 830    
Floating production storage and offloading vessels (FPSO)      
Right-of-use assets      
Net carrying amount - beginning of period 2,606 1,977  
Additions   630  
Depreciation (176) (146)  
Currency translation differences (295) 145  
Other changes (1)    
Net carrying amount - end of period 2,134 2,606 1,977
Drilling rig      
Right-of-use assets      
Net carrying amount - beginning of period 419 449  
Additions 266 294  
Depreciation (248) (342)  
Currency translation differences (32) 19  
Changes in the scope of consolidation   38  
Other changes (53) (39)  
Net carrying amount - end of period 352 419 449
Drilling rig | Exploration & Production      
Right-of-use assets      
Additions 266    
Naval facilities and related logistic bases for oil and gas transportation      
Right-of-use assets      
Net carrying amount - beginning of period 1,005 724  
Additions 566 690  
Depreciation (496) (391)  
Impairments   (4)  
Currency translation differences (14) 5  
Other changes (44) (19)  
Net carrying amount - end of period 1,017 1,005 724
Motorway concessions and service stations      
Right-of-use assets      
Net carrying amount - beginning of period 452 492  
Additions 91 59  
Depreciation (76) (79)  
Impairments (11) (21)  
Currency translation differences 1 (1)  
Other changes (7) 2  
Net carrying amount - end of period 450 452 492
Motorway concessions and service stations | Enilive, Refining and Chemicals [member]      
Right-of-use assets      
Additions 141    
Oil and gas distribution facilities      
Right-of-use assets      
Net carrying amount - beginning of period 36 17  
Additions 10 53  
Depreciation (20) (22)  
Impairments (1) (10)  
Other changes (2) (2)  
Net carrying amount - end of period 23 36 17
Oil and gas distribution facilities | Exploration & Production      
Right-of-use assets      
Additions 535    
Oil and gas distribution facilities | Exploration & Production | Eni Trade and Biofuels SpA      
Right-of-use assets      
Additions 115    
Office buildings      
Right-of-use assets      
Net carrying amount - beginning of period 487 580  
Additions 138 52  
Depreciation (120) (132)  
Currency translation differences (10) 7  
Changes in the scope of consolidation   5  
Other changes (3) (25)  
Net carrying amount - end of period 492 487 580
Office buildings | Italy      
Right-of-use assets      
Lease commitment, nominal value € 331    
Lease commitment, term of contract 20 years    
Lessee's exposure arising from options for extension or termination of lease for office buildings € 166    
Vehicles      
Right-of-use assets      
Net carrying amount - beginning of period 21 17  
Additions 20 19  
Depreciation (10) (14)  
Changes in the scope of consolidation   1  
Other changes (5) (2)  
Net carrying amount - end of period 26 21 17
Other      
Right-of-use assets      
Net carrying amount - beginning of period 796 578  
Additions 59 317  
Depreciation (98) (73)  
Impairments (2) (5)  
Currency translation differences (36) 18  
Changes in the scope of consolidation   (2)  
Other changes (29) (37)  
Net carrying amount - end of period 690 796 € 578
Assets for staff activities | Corporate and Other activities | Italy      
Right-of-use assets      
Additions 122    
Gross carrying amount      
Right-of-use assets      
Net carrying amount - beginning of period 9,690    
Net carrying amount - end of period 9,892 9,690  
Gross carrying amount | Floating production storage and offloading vessels (FPSO)      
Right-of-use assets      
Net carrying amount - beginning of period 3,217    
Net carrying amount - end of period 2,844 3,217  
Gross carrying amount | Drilling rig      
Right-of-use assets      
Net carrying amount - beginning of period 1,235    
Net carrying amount - end of period 1,309 1,235  
Gross carrying amount | Naval facilities and related logistic bases for oil and gas transportation      
Right-of-use assets      
Net carrying amount - beginning of period 2,095    
Net carrying amount - end of period 2,490 2,095  
Gross carrying amount | Motorway concessions and service stations      
Right-of-use assets      
Net carrying amount - beginning of period 873    
Net carrying amount - end of period 954 873  
Gross carrying amount | Oil and gas distribution facilities      
Right-of-use assets      
Net carrying amount - beginning of period 97    
Net carrying amount - end of period 101 97  
Gross carrying amount | Office buildings      
Right-of-use assets      
Net carrying amount - beginning of period 1,067    
Net carrying amount - end of period 1,142 1,067  
Gross carrying amount | Vehicles      
Right-of-use assets      
Net carrying amount - beginning of period 57    
Net carrying amount - end of period 53 57  
Gross carrying amount | Other      
Right-of-use assets      
Net carrying amount - beginning of period 1,049    
Net carrying amount - end of period 999 1,049  
Provisions for depreciation and impairment      
Right-of-use assets      
Net carrying amount - beginning of period (3,868)    
Net carrying amount - end of period (4,708) (3,868)  
Provisions for depreciation and impairment | Floating production storage and offloading vessels (FPSO)      
Right-of-use assets      
Net carrying amount - beginning of period (611)    
Net carrying amount - end of period (710) (611)  
Provisions for depreciation and impairment | Drilling rig      
Right-of-use assets      
Net carrying amount - beginning of period (816)    
Net carrying amount - end of period (957) (816)  
Provisions for depreciation and impairment | Naval facilities and related logistic bases for oil and gas transportation      
Right-of-use assets      
Net carrying amount - beginning of period (1,090)    
Net carrying amount - end of period (1,473) (1,090)  
Provisions for depreciation and impairment | Motorway concessions and service stations      
Right-of-use assets      
Net carrying amount - beginning of period (421)    
Net carrying amount - end of period (504) (421)  
Provisions for depreciation and impairment | Oil and gas distribution facilities      
Right-of-use assets      
Net carrying amount - beginning of period (61)    
Net carrying amount - end of period (78) (61)  
Provisions for depreciation and impairment | Office buildings      
Right-of-use assets      
Net carrying amount - beginning of period (580)    
Net carrying amount - end of period (650) (580)  
Provisions for depreciation and impairment | Vehicles      
Right-of-use assets      
Net carrying amount - beginning of period (36)    
Net carrying amount - end of period (27) (36)  
Provisions for depreciation and impairment | Other      
Right-of-use assets      
Net carrying amount - beginning of period (253)    
Net carrying amount - end of period € (309) € (253)