Profit Or Loss [Abstract]
| Concept | 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 | 
|---|---|---|---|---|
| Profit or loss [abstract] | ||||
| Profit (loss) [abstract] | ||||
| Revenue | — | — | — | — | 
| Interest revenue calculated using effective interest method | 
                                                354,987
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                322,297
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Other gains (losses) | 
                                                72,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                229,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Gain (loss) arising from derecognition of financial assets measured at amortised cost | 
                                                233,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                917,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Impairment loss (impairment gain and reversal of impairment loss) determined in accordance with IFRS 9 | 
                                                40,115
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                38,360
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Share of profit (loss) of associates and joint ventures accounted for using equity method | 
                                                78,912
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                90,432
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Profit (loss) before tax | 
                                                186,797
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                206,272
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Tax expense (income) | 
                                                23,560
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                27,204
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Profit (loss) | 
                                                163,236
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                163,236
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                179,068
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                179,068
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Earnings per share [text block] | — | — | — | — | 
| Earnings per share [abstract] | ||||
| Earnings per share [line items] | ||||
| Basic earnings per share [abstract] | ||||
| Basic earnings (loss) per share | 
                                                351.00
                                                
                                             | — | — | 
                                                398.00
                                                
                                             | 
| Diluted earnings per share [abstract] | ||||
| Diluted earnings (loss) per share | 
                                                351.00
                                                
                                             | — | — | 
                                                398.00
                                                
                                             |