Statement Of Changes In Equity [Abstract]
| Concept | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 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 | As at 2023-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | 2022-01-01 to 2022-12-31 | 2022-01-01 to 2022-12-31 | 2022-01-01 to 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | |||||||||||||||||||||||||
| Statement of changes in equity [line items] | |||||||||||||||||||||||||
| Equity | — | 
                                                1 650 516
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                1 379 074
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                50 453
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                37 275
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                183  714
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 530 241
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
                                                73  153
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1  306  010
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                36  559
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                114  519
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                1 158 416
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                31  443
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                114  519
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 340 937
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                36  559
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Changes in equity [abstract] | |||||||||||||||||||||||||
| Comprehensive income [abstract] | |||||||||||||||||||||||||
| Profit (loss) | 
                                                175  397
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                175  397
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                249  068
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                249   068
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Other comprehensive income | 
                                                22 700
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                22  700
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                41  710
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                41  710
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Comprehensive income | 
                                                152  697
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                22 700
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                175  397
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                41  710
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                290  778
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                249  068
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — |