Statement Of Changes In Equity [Abstract]
| Concept | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | 2024-01-01 to 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 | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | As at 2024-12-31 | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 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 | As at 2022-12-31 | As at 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Equity | — | — | — | — | 
                                                4,528,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                4,070,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                34,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                47,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                109,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                8,779,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                432,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                1,007,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                9,833,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                175,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                288,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | 
                                                9,377,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                4,147,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | 
                                                35,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                4,070,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                34,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                7,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                8,339,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                383,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                1,004,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                6,177,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                168,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                27,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,533,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                3,569,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                79,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                24,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                5,146,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                266,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,004,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Changes in equity [abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Comprehensive income [abstract] | ||||||||||||||||||||||||||||||||||||||||||||||||||
| Profit (loss) | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                946,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | 
                                                946,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                944,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,086,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                1,086,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,086,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Other comprehensive income | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                276,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | 
                                                114,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                276,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                49,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                113,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                61,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                120,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                61,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                65,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | 
                                                117,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Comprehensive income | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,221,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,059,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                1,220,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                49,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                113,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,147,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                120,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                1,147,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,151,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | 
                                                117,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Dividends recognised as distributions to owners | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                627,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | 
                                                627,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                3,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                629,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                484,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                482,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                2,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                482,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Increase (decrease) through other changes, equity | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                17,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | 
                                                17,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                22,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                5,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                8,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                2,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                7,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Increase (decrease) through treasury share transactions, equity | 
                                                102,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                103,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                103,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                4,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                5,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                5,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Increase (decrease) through changes in ownership interests in subsidiaries that do not result in loss of control, equity | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                14,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | 
                                                14,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                -
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — |