Profit Or Loss [Abstract]
| Concept | 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 | 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 | 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 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Profit or loss [abstract] | ||||||||||||||
| Profit (loss) [abstract] | ||||||||||||||
| Profit (loss) from operating activities | — | — | 
                                                295,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                376,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Finance income | — | — | 
                                                18,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                5,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Finance costs | — | — | 
                                                18,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                16,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Profit (loss) before tax | — | — | 
                                                295,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                365,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Tax expense (income) | — | — | 
                                                66,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                80,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Profit (loss) | 
                                                13,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                229,000,000
                                                
                                                    
                                                        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
                                                    
                                                
                                             | 
| Profit (loss), attributable to [abstract] | ||||||||||||||
| Profit (loss), attributable to owners of parent | — | — | 
                                                216,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                275,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Profit (loss), attributable to non-controlling interests | — | — | 
                                                13,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                10,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Earnings per share [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Earnings per share [abstract] | ||||||||||||||
| Earnings per share [line items] | ||||||||||||||
| Basic earnings per share [abstract] | ||||||||||||||
| Basic earnings (loss) per share | — | — | 
                                                142.00
                                                
                                             | — | — | — | — | — | — | 
                                                181.00
                                                
                                             | — | — | — | — | 
| Diluted earnings per share [abstract] | ||||||||||||||
| Diluted earnings (loss) per share | — | — | 
                                                142.00
                                                
                                             | — | — | — | — | — | — | 
                                                181.00
                                                
                                             | — | — | — | — |