Segment Information - Summary of Reconciliation from Operating Result Before Tax to Income Before Tax (Parenthetical) (Detail) - EUR (€) € in Millions |
6 Months Ended | |
|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Disclosure of reconciliation from operating result before tax to income before tax [Line Items] | ||
| Experience adjustments that relate to current service included in other income charges | € 2 | € 41 |
| Gain (loss) on reversal of onerous contracts | 185 | 14 |
| Other income / (charges) [member] | ||
| Disclosure of reconciliation from operating result before tax to income before tax [Line Items] | ||
| Loss on onerous contracts | 511 | 181 |
| Insurance contracts issued [member] | ||
| Disclosure of reconciliation from operating result before tax to income before tax [Line Items] | ||
| Gain (loss) on changes in fair value of variable fee approach products | € (552) | € (239) |