Statement Of Financial Position [Abstract]
| 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 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 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||
| Non-current assets [abstract] | ||||||||||||||||||
| Property, plant and equipment | — | — | 
                                                5,149,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                5,224,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Right-of-use assets | — | — | 
                                                559,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                560,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Deferred tax assets | — | — | 
                                                195,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                329,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Other non-current financial assets | — | — | 
                                                154,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                167,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Other non-current non-financial assets | — | — | 
                                                2,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Non-current assets | — | — | 
                                                6,245,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                6,544,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Current assets [abstract] | ||||||||||||||||||
| Current inventories | — | — | 
                                                4,795,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                4,191,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Current tax assets, current | — | — | 
                                                18,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                –
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Other current financial assets | — | — | 
                                                139,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                113,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Other current non-financial assets | — | — | 
                                                126,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                212,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Cash and cash equivalents | — | — | 
                                                1,078,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,081,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,166,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | 
| Current assets | — | — | 
                                                8,095,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                7,565,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Assets | — | — | 
                                                1,434,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,410,900
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Equity and liabilities [abstract] | ||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||
| Issued capital | — | — | 
                                                396,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                396,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Retained earnings | — | — | 
                                                2,745,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                2,498,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Share premium | — | — | 
                                                2,198,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                2,198,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Other reserves | — | — | 
                                                32,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                103,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Equity attributable to owners of parent | — | — | 
                                                5,307,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                4,989,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Equity | 
                                                2,745,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,198,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                5,307,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                396,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                53,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                85,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,198,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                396,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                11,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                115,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,498,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                4,989,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                3,711,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,232,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                396,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                20,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,198,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                95,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Liabilities [abstract] | ||||||||||||||||||
| Non-current liabilities [abstract] | ||||||||||||||||||
| Non-current provisions [abstract] | ||||||||||||||||||
| Non-current provisions for employee benefits | — | — | 
                                                917,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                911,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Other non-current provisions | — | — | 
                                                138,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                48,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Deferred tax liabilities | — | — | 
                                                11,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                11,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Other non-current non-financial liabilities | — | — | 
                                                7,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                –
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Non-current liabilities | — | — | 
                                                7,432,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                5,267,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Current liabilities [abstract] | ||||||||||||||||||
| Current provisions [abstract] | ||||||||||||||||||
| Current provisions | — | — | 
                                                182,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                231,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Current tax liabilities, current | — | — | 
                                                11,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                9,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Other current non-financial liabilities | — | — | 
                                                140,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                229,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Current liabilities | — | — | 
                                                1,601,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                3,853,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Liabilities | — | — | 
                                                9,033,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                9,120,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Equity and liabilities | — | — | 
                                                1,434,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,410,900
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — |