Basis of preparation and significant changes in the current reporting period - Reconciliation shareholders' equity under IFRS-EU and IFRS-IASB (Details) - EUR (€) € in Millions |
Jun. 30, 2025 |
Dec. 31, 2024 |
Jun. 30, 2024 |
|---|---|---|---|
| Disclosure of Reconciliation Shareholder Equity EU IFRS and IASB IFRS [Abstract] | |||
| In accordance with IFRS-EU (attributable to the shareholders of the parent) | € 49,115 | € 50,147 | |
| Adjustment of the EU IAS 39 carve-out | 4,443 | 6,413 | |
| Tax effect of the adjustment | (1,268) | (1,871) | |
| Effect of adjustment after tax | 3,175 | 4,542 | |
| In accordance with IFRS-IASB Shareholders’ equity | € 52,290 | € 52,703 | € 54,689 |