Profit Or Loss [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 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Profit or loss [abstract] | ||||||||||||||||
| Profit (loss) [abstract] | ||||||||||||||||
| Other income | — | — | 
                                                628,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                554,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Profit (loss) from operating activities | — | — | 
                                                12 385
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                13 183
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Finance income | — | — | 
                                                470,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                349,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Finance costs | — | — | 
                                                1 416
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1 297
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Share of profit (loss) of associates and joint ventures accounted for using equity method | — | — | 
                                                20,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                15,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Profit (loss) before tax | — | — | 
                                                11 439
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                12 235
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Tax expense (income) | — | — | 
                                                2 683
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                2 777
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Profit (loss) | 
                                                25,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                8 756
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                8 731
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                8 731
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9 458
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                27,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9 431
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                9 431
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Profit (loss), attributable to [abstract] | ||||||||||||||||
| Profit (loss), attributable to owners of parent | — | — | 
                                                8 731
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                9 431
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Profit (loss), attributable to non-controlling interests | — | — | 
                                                25,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                27,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
| Earnings per share [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Earnings per share [abstract] | ||||||||||||||||
| Earnings per share [line items] | ||||||||||||||||
| Basic earnings per share [abstract] | ||||||||||||||||
| Basic earnings (loss) per share | — | — | 
                                                7 .23
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                7 .82
                                                
                                             | — | — | — | — | 
| Diluted earnings per share [abstract] | ||||||||||||||||
| Diluted earnings (loss) per share | — | — | 
                                                7 .23
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                7 .81
                                                
                                             | — | — | — | — |