Capital and financial risk management - Market risk - Interest rate management (Details) - EUR (€) € in Millions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| Interest rate risk | ||
| Capital and financial risk management | ||
| Percentage of reasonably possible increase in risk assumption | 1.00% | |
| Increase in profit before tax due to reasonably possible increase in designated risk component | € 19 | € 39 |
| Increase in profit before tax due to reasonably possible decrease in designated risk component | € 9 | 26 |
| Currency risk [member] | ||
| Capital and financial risk management | ||
| Percentage Of Reasonably Possible Decrease In Risk Assumption | 10.00% | |
| Currency risk [member] | United States of America, Dollars | ||
| Capital and financial risk management | ||
| Percentage of reasonably possible increase in risk assumption | 10.00% | |
| Decrease in Equity Due to Sensitivity to Foreign Exchange Movements | € 192 | € 304 |
| Percentage Of Reasonably Possible Decrease In Risk Assumption | 10.00% |