Analysis Of Income And Expense [Abstract]
| Concept | 
                                    
                                        2024-01-01 to 2024-12-31  | 
                            
                                
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                        
|---|---|---|
| Analysis of income and expense [abstract] | ||
| Revenue [abstract] | ||
| Revenue | 
                                        
                                             
                                                370,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Material income and expense [abstract] | ||
| Gains (losses) on disposals of investments [abstract] | ||
| Gains (losses) on disposals of investments | 
                                        
                                             
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Other reversals of provisions | 
                                        
                                             
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Finance income (cost) | — | — | 
| Other finance income (cost) | 
                                        
                                             
                                                217,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                246,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Revenue and other operating income | 
                                        
                                             
                                                370,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Expenses by nature [abstract] | ||
| Other expenses, by nature | 
                                        
                                             
                                                471,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                520,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Share of profit (loss) of associates and joint ventures accounted for using equity method [abstract] | ||
| Share of profit (loss) of associates and joint ventures accounted for using equity method | 
                                        
                                             
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                0
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             
                                        
                                     |