Debt, cash and cash equivalents - Summary of Market Value of Net Debt (Details) - EUR (€) € in Millions |
6 Months Ended | 12 Months Ended |
|---|---|---|
Jun. 30, 2026 |
Dec. 31, 2025 |
|
| Disclosure of detailed information about borrowings [Line Items] | ||
| Market value | € 21,893 | € 18,702 |
| Market value | ||
| Disclosure of detailed information about borrowings [Line Items] | ||
| Market value | 14,989 | 10,424 |
| Value on redemption | ||
| Disclosure of detailed information about borrowings [Line Items] | ||
| Market value | 21,868 | 18,716 |
| Value on redemption | € 15,488 | € 11,022 |