v3.26.1
Business combinations and other significant transactions - Divestments - Additional Information (Details) - EUR (€)
€ in Millions
12 Months Ended
Dec. 18, 2025
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Business combinations and other significant transactions        
Cash and cash equivalents   € 40 € 153 € 25
Capital gain realized from the sale of investments   77 € 562 € 430
Other current financial assets   45    
Eni CCUS Holding        
Business combinations and other significant transactions        
Cash and cash equivalents   40    
Other current financial assets   € 45    
Eni CCUS Holding | Liverpool Bay CCS Ltd        
Business combinations and other significant transactions        
Proportion of ownership interest in subsidiary 100.00%      
Eni CCUS Holding | Global Infrastructure Partners (GIP)        
Business combinations and other significant transactions        
Cash and cash equivalents € 40      
Net assets and liabilities derecognized 222      
Capital gain realized from the sale of investments € 46      
Equity interest disposed (as a percent) 49.99%      
Other current financial assets € 45      
Fair value of joint venture € 27