Disclosure Of Effect Of Changes In Foreign Exchange Rates [Text Block]
| Concept | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | 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 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Disclosure of effect of changes in foreign exchange rates [text block] | — |  | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Description of presentation currency | — | 
                                                svenska
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Reserve of exchange differences on translation | — | — | — | 
                                                23,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                14,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Disclosure of information when currency is not exchangeable into another currency [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of information when foreign operation’s functional currency is not exchangeable into presentation currency [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of summarised financial information about foreign operation [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of summarised financial information about foreign operation [abstract] | ||||||||||||||||
| Disclosure of summarised financial information about foreign operation [line items] | ||||||||||||||||
| Non-current assets | — | — | — | 
                                                348,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                345,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Current assets | — | — | — | 
                                                765,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                667,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Non-current liabilities | — | — | — | 
                                                97,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                108,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Current liabilities | — | — | — | 
                                                283,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                261,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Profit (loss) | 
                                                13,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                229,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                216,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                216,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                285,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                10,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                275,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                275,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Comprehensive income | 
                                                14,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                238,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                9,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                225,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                216,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                284,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                10,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                275,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                274,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             |