Disclosure Of Fair Value Measurement [Text Block]
| Concept | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Disclosure of fair value measurement [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of fair value measurement of assets [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of fair value measurement of assets [abstract] | ||||||||||||||||||||||||
| Disclosure of fair value measurement of assets [line items] | ||||||||||||||||||||||||
| Assets | — | — | — | — | — | — | — | 
                                                83 589
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                67 784
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Reconciliation of changes in fair value measurement, assets [abstract] | ||||||||||||||||||||||||
| Disclosure of fair value measurement of equity [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of fair value measurement of equity [abstract] | ||||||||||||||||||||||||
| Disclosure of fair value measurement of equity [line items] | ||||||||||||||||||||||||
| Equity | 
                                                39 947
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                500,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                423,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                2 192
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                42 757
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                117,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                43 180
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                37 210
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                35 452
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                388,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                500,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                735,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                36 822
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                30,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                105,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                33 508
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                488,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                30 228
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                500,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                2 091
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                33 020
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                107,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                94,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Reconciliation of changes in fair value measurement, entity's own equity instruments [abstract] |