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, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Disclosure of Reconciliation Shareholder Equity EU IFRS and IASB IFRS [Abstract] | ||
| In accordance with IFRS-EU (attributable to the shareholders of the parent) | € 50,246 | € 49,698 |
| Adjustment of the EU IAS 39 carve-out | 5,582 | 6,022 |
| Tax effect of the adjustment | (1,516) | (1,636) |
| Effect of adjustment after tax | 4,067 | 4,386 |
| In accordance with IFRS-IASB Shareholders’ equity | € 54,313 | € 54,083 |