v3.26.1
Financial instruments - Fair values and risk management - Fair value (Details) - EUR (€)
€ in Millions
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Financial assets and liabilities for which fair value is disclosed, at fair value      
Disclosure of detailed information about financial instruments [line items]      
Financial assets and liabilities at fair value € 3,720.6 € 2,848.7 € 3,045.2
At fair value      
Disclosure of detailed information about financial instruments [line items]      
Assets measured at fair value 2,226.3 109.8 352.8
Liabilities measured at fair value 150.1 227.2 182.1
Not measured at fair value      
Disclosure of detailed information about financial instruments [line items]      
Liabilities measured at fair value 1,344.2 2,511.7 2,510.3
Level 2 | Financial assets and liabilities for which fair value is disclosed, at fair value      
Disclosure of detailed information about financial instruments [line items]      
Financial assets and liabilities at fair value 3,720.6 2,848.7 3,045.2
Level 2 | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Assets measured at fair value 2,226.3 109.8 352.8
Liabilities measured at fair value 150.1 227.2 182.1
Level 2 | Not measured at fair value      
Disclosure of detailed information about financial instruments [line items]      
Liabilities measured at fair value 1,344.2 2,511.7 2,510.3
Foriegn currency forward contracts | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Liabilities measured at fair value 79.6 2.7 3.3
Foriegn currency forward contracts | Level 2 | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Liabilities measured at fair value 79.6 2.7 3.3
Jet fuel and carbon derivative contracts | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Liabilities measured at fair value 70.5 224.5 178.8
Jet fuel and carbon derivative contracts | Level 2 | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Liabilities measured at fair value 70.5 224.5 178.8
Debt | Not measured at fair value      
Disclosure of detailed information about financial instruments [line items]      
Liabilities measured at fair value 1,344.2 2,511.7 2,510.3
Debt | Level 2 | Not measured at fair value      
Disclosure of detailed information about financial instruments [line items]      
Liabilities measured at fair value 1,344.2 2,511.7 2,510.3
Foriegn currency forward contracts      
Disclosure of detailed information about financial instruments [line items]      
Notional amount 7,823.9 5,440.5 4,851.5
Foriegn currency forward contracts | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Assets measured at fair value 128.2 90.2 147.2
Foriegn currency forward contracts | Level 2 | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Assets measured at fair value 128.2 90.2 147.2
Cross-currency swaps | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Assets measured at fair value     205.6
Cross-currency swaps | Level 2 | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Assets measured at fair value     € 205.6
Jet fuel and carbon derivative contracts | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Assets measured at fair value 2,098.1 19.6  
Jet fuel and carbon derivative contracts | Level 2 | At fair value      
Disclosure of detailed information about financial instruments [line items]      
Assets measured at fair value € 2,098.1 € 19.6