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 to reconcile profit (loss) other than changes in working capital | 
                                                12,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                42,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Increase (decrease) in working capital | 
                                                103,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                19,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Adjustments for undistributed profits of investments accounted for using equity method | 
                                                1,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                25,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Income taxes paid, classified as operating activities | 
                                                18,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                13,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Cash flows from (used in) investing activities [abstract] | ||
| Purchase of financial instruments, classified as investing activities | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                10,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             |