Disclosure Of Cash Flow Statement [Text Block]
| Concept | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | 
|---|---|---|---|---|---|
| Disclosure of cash flow statement [text block] | — | — | — | — | — | 
| Cash and cash equivalents if different from statement of financial position [abstract] | |||||
| Cash and cash equivalents | — | 
                                                132,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                101,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                30,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Income taxes paid (refund) [abstract] | |||||
| Income taxes paid (refund), classified as operating activities | 
                                                72,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                156,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — |