Disclosure Of Fair Value Measurement [Text Block]
| 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 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 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 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2022-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Disclosure of fair value measurement [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of fair value measurement of assets [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of fair value measurement of assets [abstract] | ||||||||||||||||||||||||||||||||||||||||
| Disclosure of fair value measurement of assets [line items] | ||||||||||||||||||||||||||||||||||||||||
| Assets | — | — | — | — | — | — | — | — | — | 
                                                28,976,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                29,406,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Reconciliation of changes in fair value measurement, assets [abstract] | ||||||||||||||||||||||||||||||||||||||||
| Disclosure of fair value measurement of liabilities [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of fair value measurement of liabilities [abstract] | ||||||||||||||||||||||||||||||||||||||||
| Disclosure of fair value measurement of liabilities [line items] | ||||||||||||||||||||||||||||||||||||||||
| Liabilities | — | — | — | — | — | — | — | — | — | 
                                                16,933,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                17,345,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Reconciliation of changes in fair value measurement, liabilities [abstract] | ||||||||||||||||||||||||||||||||||||||||
| Disclosure of fair value measurement of equity [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of fair value measurement of equity [abstract] | ||||||||||||||||||||||||||||||||||||||||
| Disclosure of fair value measurement of equity [line items] | ||||||||||||||||||||||||||||||||||||||||
| Equity | 
                                                3,650,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                6,654,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                188,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                37,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,014,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                411,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                12,006,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                90,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                12,043,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                12,061,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                5,402,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                33,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                5,827,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                183,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,263,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                262,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                12,028,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                6,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                390,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                13,283,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                34,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                5,025,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                6,832,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                275,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                178,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,866,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                13,249,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                376,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                2,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                476,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                9,344,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                14,475,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                25,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                344,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                14,438,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                36,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                4,646,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                1,117,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
                                                177,000,000
                                                
                                                    
                                                        EUR
                                                    
                                                
                                             | 
| Reconciliation of changes in fair value measurement, entity's own equity instruments [abstract] |