Statement Of Cash Flows [Abstract]
| Concept | 
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                                
                                    
                                        As at 2023-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                                
                                    
                                        2022-01-01 to 2022-12-31  | 
                            
                                
                                    
                                        As at 2021-12-31  | 
                            
                        
|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||
| Cash flows from (used in) operating activities [abstract] | |||||
| Profit (loss) | 
                                        
                                             
                                                84  0 41
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                68  224
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Adjustments to reconcile profit (loss) [abstract] | |||||
| Adjustments for decrease (increase) in inventories | 
                                        
                                             
                                                873,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                2 7 2
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Other adjustments for non-cash items | 
                                        
                                             
                                                14 057
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                17   572
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Interest paid, classified as operating activities | 
                                        
                                             
                                                1   208
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                1   362
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Interest received, classified as operating activities | 
                                        
                                             
                                                3 503
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                4 47
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) operating activities | 
                                        
                                             
                                                56   197
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                80   613
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) investing activities [abstract] | |||||
| Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities | 
                                        
                                             
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                400,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Proceeds from sales of property, plant and equipment, classified as investing activities | 
                                        
                                             
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                2  251
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Purchase of property, plant and equipment, classified as investing activities | 
                                        
                                             
                                                7 0 0
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                5  543
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) investing activities | 
                                        
                                             
                                                7 0 0
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                8  194
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) financing activities [abstract] | |||||
| Payments of lease liabilities, classified as financing activities | 
                                        
                                             
                                                11   9 6 8
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                14  974
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash flows from (used in) financing activities | 
                                        
                                             
                                                6 4  601
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                86  028
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Effect of exchange rate changes on cash and cash equivalents [abstract] | |||||
| Effect of exchange rate changes on cash and cash equivalents | 
                                        
                                             
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Increase (decrease) in cash and cash equivalents after effect of exchange rate changes | 
                                        
                                             
                                                9  104
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
                                        
                                             
                                                13  60 9
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
| Cash and cash equivalents | — | 
                                        
                                             
                                                107  898
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                117  0 0 2
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                130    611
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             
                                        
                                     |