v3.26.1
Deferred tax assets and liabilities - Additional information (Details) - EUR (€)
€ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Deferred tax assets and liabilities      
Carry-forward tax losses € 18,575    
Carry-forward tax losses indefinitely 15,432    
Deferred tax assets € 8,848 € 9,465  
Tax rate 24.00% 24.00% 24.00%
Accumulated impairment      
Deferred tax assets and liabilities      
Deductions € (60) € (1,663)  
Italy      
Deferred tax assets and liabilities      
Carry-forward tax losses € 10,841    
Tax rate 24.00%    
Italy | Accumulated impairment      
Deferred tax assets and liabilities      
Deferred tax assets € 2,134    
Italy | Unused tax losses      
Deferred tax assets and liabilities      
Deferred tax assets 2,602    
Foreign (outside Italy)      
Deferred tax assets and liabilities      
Carry-forward tax losses € 7,734    
Tax rate 27.70%    
Foreign (outside Italy) | Accumulated impairment      
Deferred tax assets and liabilities      
Deferred tax assets € 2,021    
Foreign (outside Italy) | Unused tax losses      
Deferred tax assets and liabilities      
Deferred tax assets € 2,144