Statement Of Comprehensive Income [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 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||
| 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
                                                    
                                                
                                             | 
| Other comprehensive income [abstract] | ||||||||||||||
| Components of other comprehensive income that will be reclassified to profit or loss, net of tax [abstract] | ||||||||||||||
| Exchange differences on translation [abstract] | ||||||||||||||
| Gains (losses) on exchange differences on translation of foreign operations, net of tax | 
                                                1,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Comprehensive income | 
                                                14,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                238,000,000
                                                
                                                    
                                                        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
                                                    
                                                
                                             | 
| Comprehensive income attributable to [abstract] | ||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — | 
                                                225,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                274,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Comprehensive income, attributable to non-controlling interests | — | — | 
                                                14,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                10,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — |