Disclosure Of Interests In Other Entities [Text Block]
| Concept | 
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                                
                                    
                                        As at 2023-12-31  | 
                            
                                
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        2022-01-01 to 2022-12-31  | 
                            
                                
                                    
                                        2022-01-01 to 2022-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                        
|---|---|---|---|---|---|---|---|
| Disclosure of interests in other entities [text block] | — | — | — | — | — | — | — | 
| Disclosure of interests in subsidiaries [text block] | — | — | — | — | — | — | — | 
| Disclosure of subsidiaries [text block] | 
                                        
                                             | 
                                
                                    — | — | — | — | — | — | 
| Disclosure of subsidiaries [abstract] | |||||||
| Disclosure of subsidiaries [line items] | |||||||
| Current assets | — | 
                                        
                                             
                                                303  806
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                266  620
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
| Non-current assets | — | 
                                        
                                             
                                                15 5    6 0 7
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                167   2 2 9
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
| Current liabilities | — | 
                                        
                                             
                                                149   382
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                14 4    9 2 2
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
| Non-current liabilities | — | 
                                        
                                             
                                                25 052
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                35 356
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
| Revenue | 
                                        
                                             
                                                837  523
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                79 7    116
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Profit (loss) | 
                                        
                                             
                                                84  0 41
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                68  224
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Comprehensive income | 
                                        
                                             
                                                84  0 41
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                84  0 41
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                68  224
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                68  224
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Disclosure of interests in associates [text block] | — | — | — | — | — | — | — | 
| Disclosure of associates [text block] | — | — | — | — | — | — | — | 
| Disclosure of associates [abstract] | |||||||
| Disclosure of associates [line items] | |||||||
| Disclosure of interests in joint arrangements [text block] | — | — | — | — | — | — | — | 
| Disclosure of joint ventures [text block] | — | — | — | — | — | — | — | 
| Disclosure of joint ventures [abstract] | |||||||
| Disclosure of joint ventures [line items] | |||||||
| Cash and cash equivalents | — | 
                                        
                                             
                                                107  898
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                117  0 0 2
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                130    611
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                            
| Depreciation and amortisation expense | 
                                        
                                             
                                                14   038
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                17   355
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Tax expense (income) | 
                                        
                                             
                                                22  810
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | — | 
                                        
                                             
                                                18  790
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — |