Statement Of Cash Flows [Abstract]
| Concept | 
                                    
                                        2024-01-01 to 2024-12-31  | 
                            
                                
                                    
                                        As at 2024-12-31  | 
                            
                                
                                    
                                        2023-01-01 to 2023-12-31  | 
                            
                                
                                    
                                        As at 2023-12-31  | 
                            
                                
                                    
                                        As at 2022-12-31  | 
                            
                        
|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||
| Cash flows from (used in) operating activities [abstract] | |||||
| Cash flows from (used in) operations | 
                                        
                                             
                                                3,302,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                3,160,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Interest paid, classified as operating activities | 
                                        
                                             
                                                434,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                428,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Interest received, classified as operating activities | 
                                        
                                             
                                                92,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                81,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Income taxes paid (refund), classified as operating activities | 
                                        
                                             
                                                235,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                175,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Cash flows from (used in) operating activities | 
                                        
                                             
                                                2,725,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                2,638,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Cash flows from (used in) investing activities [abstract] | |||||
| Cash flows from losing control of subsidiaries or other businesses, classified as investing activities | 
                                        
                                             
                                                135,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                441,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities | 
                                        
                                             
                                                35,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                36,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Purchase of property, plant and equipment, classified as investing activities | 
                                        
                                             
                                                120,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                93,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Purchase of other long-term assets, classified as investing activities | 
                                        
                                             
                                                189,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                131,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Cash flows from (used in) investing activities | 
                                        
                                             
                                                1,544,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                1,141,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Cash flows from (used in) financing activities [abstract] | |||||
| Proceeds from borrowings, classified as financing activities | 
                                        
                                             
                                                -
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                254,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Repayments of borrowings, classified as financing activities | 
                                        
                                             
                                                1,086,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                3,273,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Payments of lease liabilities, classified as financing activities | 
                                        
                                             
                                                99,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                -
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Dividends paid, classified as financing activities | 
                                        
                                             
                                                -
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                32,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Other inflows (outflows) of cash, classified as financing activities | 
                                        
                                             
                                                -
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                71,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Cash flows from (used in) financing activities | 
                                        
                                             
                                                2,365,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                312,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes | 
                                        
                                             
                                                1,184,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                1,185,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Effect of exchange rate changes on cash and cash equivalents [abstract] | |||||
| Effect of exchange rate changes on cash and cash equivalents | 
                                        
                                             
                                                2,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                13,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | — | 
| Cash and cash equivalents | — | 
                                        
                                             
                                                980,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    — | 
                                        
                                             
                                                2,162,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     | 
                                
                                    
                                        
                                             
                                                990,000,000
                                                
                                                    
                                                        DKK
                                                    
                                                
                                             
                                        
                                     |