Disclosure Of Interests In Other Entities [Text Block]
| Concept | 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 | 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 | 2022-01-01 to 2022-12-31 | As at 2021-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Disclosure of interests in other entities [text block] | — | — |  | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of interests in subsidiaries [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of subsidiaries [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of subsidiaries [abstract] | |||||||||||||
| Disclosure of subsidiaries [line items] | |||||||||||||
| Current assets | — | — | — | 
                                                1 668 944
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                1 723 807
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Non-current assets | — | — | — | 
                                                2 091 756
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                1 881 732
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Current liabilities | — | — | — | 
                                                909  119
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                949  798
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Non-current liabilities | — | — | — | 
                                                1 201 065
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                1 125 500
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Revenue | — | — | 
                                                3 431 455
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                3 508 706
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | 
| Profit (loss) | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                175  397
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                175  397
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                249  068
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                249   068
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                152  697
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                175  397
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                22 700
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                41  710
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                290  778
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                249  068
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
| Disclosure of interests in associates [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of associates [text block] | — | — |  | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of associates [abstract] | |||||||||||||
| Disclosure of associates [line items] | |||||||||||||
| Other comprehensive income | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                22 700
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                22  700
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                41  710
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                41  710
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
| Disclosure of interests in joint arrangements [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of joint ventures [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of joint ventures [abstract] | |||||||||||||
| Disclosure of joint ventures [line items] | |||||||||||||
| Cash and cash equivalents | — | — | — | 
                                                308  936
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | 
                                                178  334
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
                                                345  864
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Tax expense (income) | — | — | 
                                                51 273
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                59 929
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — |