Statement Of Cash Flows [Abstract]
| Concept | 2024-01-01 to 2024-12-31 | 2023-01-01 to 2023-12-31 | 
|---|---|---|
| Statement of cash flows [abstract] | ||
| Cash flows from (used in) operating activities [abstract] | ||
| Adjustments for finance income (cost) | 
                                                447,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                599,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Cash flows from (used in) operations before changes in working capital | 
                                                11 317
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                11 425
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Increase (decrease) in working capital | 
                                                57 4
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                3 708
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Adjustments for decrease (increase) in trade and other receivables | 
                                                1 620
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                1 450
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Adjustments for increase (decrease) in trade and other payables | 
                                                543,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                176,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Adjustments for depreciation and amortisation expense and impairment loss (reversal of impairment loss) recognised in profit or loss | 
                                                3 444
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                2 663
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Cash flows from (used in) financing activities [abstract] | ||
| Dividends paid to equity holders of parent, classified as financing activities | 
                                                4 591
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                4 103
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Dividends paid to non-controlling interests, classified as financing activities | 
                                                2,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                3,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
| Proceeds from sale or issue of treasury shares | 
                                                290,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             | 
                                                279,000,000
                                                
                                                    
                                                        SEK
                                                    
                                                
                                             |