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 | 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 | 2023-01-01 to 2023-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||||
| Profit (loss) | 
                                                25,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                8 756
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                8 731
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                8 731
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9 458
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                27,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9 431
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9 431
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Other comprehensive income [abstract] | ||||||||||||||||
| Other comprehensive income that will not be reclassified to profit or loss, net of tax | — | 
                                                159,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                306,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Other comprehensive income that will be reclassified to profit or loss, net of tax | — | 
                                                1 430
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1 436
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Other comprehensive income | 
                                                3,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 589
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                29,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 456
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                159,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 586
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 742
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 356
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                16,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                64,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                306,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 726
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Comprehensive income | 
                                                28,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                10 345
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                29,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 456
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                8 890
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                10 317
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                7 716
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 356
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                10,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                64,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9 126
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                7 706
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Comprehensive income attributable to [abstract] | ||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | 
                                                10 317
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                7 706
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Comprehensive income, attributable to non-controlling interests | — | 
                                                28,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                10,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — |