Statement Of Comprehensive Income [Abstract]
| Concept | 
                                    
                                        2024-01-01 to 2024-12-31  | 
                            
                                
                                    
                                        2024-01-01 to 2024-12-31  | 
                            
                                
                                    
                                        2024-01-01 to 2024-12-31  | 
                            
                                
                                    
                                        2024-01-01 to 2024-12-31  | 
                            
                                
                                    
                                        2024-01-01 to 2024-12-31  | 
                            
                                
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                                
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                                
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                                
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                                
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                        
|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||
| Profit (loss) | — | 
                                        
                                             
                                                2,403,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                2,697,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
| Other comprehensive income [abstract] | ||||||||||
| Other comprehensive income that will not be reclassified to profit or loss, net of tax | — | 
                                        
                                             
                                                4,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                5,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
| Other comprehensive income that will be reclassified to profit or loss, net of tax | — | 
                                        
                                             
                                                90,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                532,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — | 
| Comprehensive income | 
                                        
                                             
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                2,308,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                2,403,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                94,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                2,308,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                3,224,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                2,697,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                527,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                3,224,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Comprehensive income attributable to [abstract] | ||||||||||
| Comprehensive income, attributable to owners of parent | — | 
                                        
                                             
                                                2,308,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                3,224,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | — |