Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept | As at 2023-12-31 | As at 2022-12-31 | As at 2021-12-31 | 
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment | 
                                                10 043
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                7 327
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Intangible assets and goodwill [abstract] | |||
| Intangible assets other than goodwill [abstract] | |||
| Intangible assets other than goodwill | 
                                                18,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                4,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Goodwill | 
                                                2 356
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                1 623
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Investment property [abstract] | |||
| Investment property | 
                                                12 795
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                12 795
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements [abstract] | |||
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements | 
                                                589,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                673,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Trade and other non-current receivables [abstract] | |||
| Trade and other non-current receivables | 
                                                103,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables | 
                                                10 496
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                23 286
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Classes of current inventories [abstract] | |||
| Current inventories | 
                                                4,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                1,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Classes of current inventories, alternative [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents | 
                                                1 193
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                1 737
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                1 213
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
| Trade and other non-current payables [abstract] | |||
| Trade and other non-current payables | 
                                                435,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                342,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Trade and other current payables [abstract] | |||
| Trade and other current payables | 
                                                1 684
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                893,000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Issued capital [abstract] | |||
| Issued capital | 
                                                35 836
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                35 836
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Retained earnings [abstract] | |||
| Retained earnings, profit (loss) for reporting period | 
                                                2  028
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                1 681
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Retained earnings, excluding profit (loss) for reporting period | 
                                                4 908
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                3 303
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Miscellaneous equity [abstract] | |||
| Additional paid-in capital | 
                                                9 000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                9 000
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Net assets (liabilities) [abstract] | |||
| Assets | 
                                                107 500
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                101 306
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Liabilities | 
                                                52 525
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                48 361
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Net current assets (liabilities) [abstract] | |||
| Current assets | 
                                                81 596
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                78 884
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Current liabilities | 
                                                29 526
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | 
                                                23 266
                                                
                                                    
                                                        BGN
                                                    
                                                
                                             | — | 
| Assets less current liabilities [abstract] |