Disclosure Of Interests In Other Entities [Text Block]
| Concept | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | As at 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 | As at 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 | As at 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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] | |||||||||||||||||
| Profit (loss), attributable to non-controlling interests | — | 
                                                13,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                10,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Non-controlling interests | — | — | — | 
                                                39,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                32,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Current assets | — | — | — | 
                                                765,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                667,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Non-current assets | — | — | — | 
                                                348,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                345,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Current liabilities | — | — | — | 
                                                283,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                261,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Non-current liabilities | — | — | — | 
                                                97,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                108,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Profit (loss) | 
                                                13,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                229,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                216,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                216,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                285,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                10,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                275,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                275,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                14,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                238,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                9,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                225,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                216,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                284,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
                                                10,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                275,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                274,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | 
| Disclosure of interests in associates [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of associates [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of associates [abstract] | |||||||||||||||||
| Disclosure of associates [line items] | |||||||||||||||||
| 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 | — | — | — | 
                                                132,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                101,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | 
                                                30,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Other current financial liabilities | — | — | — | 
                                                0
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                0
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | 
| Tax expense (income) | — | 
                                                66,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                80,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — |