v3.26.1
Financial instruments - Fair values and risk management - Jet fuel and carbon credits price risk (Details)
€ in Millions
12 Months Ended
Mar. 31, 2026
EUR (€)
£ / Right
€ / Right
$ / t
Mar. 31, 2025
EUR (€)
£ / Right
€ / Right
$ / t
Mar. 31, 2024
EUR (€)
$ / t
Jet fuel risk      
Disclosure of detailed information about financial instruments [line items]      
Percentage of Reasonably Possible Increase (decrease) in Risk Assumption 10.00%    
Increase (Decrease) in Profit and Loss Due to Reasonably Possible Decrease in Designated Risk Component € 0 € 0  
Percentage of Reasonably Possible Decrease in Risk Assumption 10.00%    
Increase (Decrease) in Profit and Loss Due to Reasonably Possible Increase in Designated Risk Component € 0 0  
Percentage of Reasonably Possible Increase in Risk Assumption 10.00%    
Increase (Decrease) In Equity Due To Reasonably Possible decrease In Designated Risk Component € (410) (286)  
Increase (Decrease) In Equity Due To Reasonably Possible Increase In Designated Risk Component € 410 286  
Jet fuel risk | Cash Flow Hedges      
Disclosure of detailed information about financial instruments [line items]      
Hedging percentage, policy 90.00%    
Estimated percentage of jet fuel expenses covered by hedging contracts as of reporting date 80.00%    
Jet fuel risk | Cash Flow Hedges | Jet Fuel Hedges      
Disclosure of detailed information about financial instruments [line items]      
Hedge ineffectiveness charge € 0 0 € 0
Jet fuel risk | Cash Flow Hedges | Jet fuel forward contracts      
Disclosure of detailed information about financial instruments [line items]      
Notional amount € 2,600 € 3,500 € 2,700
Average price of hedging instrument | $ / t 668 761 795
Jet fuel risk | Minimum | Cash Flow Hedges      
Disclosure of detailed information about financial instruments [line items]      
Hedging contracts, period covered 18 months    
Jet fuel risk | Maximum | Cash Flow Hedges      
Disclosure of detailed information about financial instruments [line items]      
Hedging contracts, period covered 24 months    
Carbon price risk      
Disclosure of detailed information about financial instruments [line items]      
Percentage of Reasonably Possible Increase (decrease) in Risk Assumption 10.00%    
Increase (Decrease) in Profit and Loss Due to Reasonably Possible Decrease in Designated Risk Component € 0 € 0  
Percentage of Reasonably Possible Decrease in Risk Assumption 10.00%    
Increase (Decrease) in Profit and Loss Due to Reasonably Possible Increase in Designated Risk Component € 0 0  
Percentage of Reasonably Possible Increase in Risk Assumption 10.00%    
Increase (Decrease) In Equity Due To Reasonably Possible decrease In Designated Risk Component € (63) (37)  
Increase (Decrease) In Equity Due To Reasonably Possible Increase In Designated Risk Component € 63 € 37  
Carbon price risk | Cash Flow Hedges | Carbon rights contracts      
Disclosure of detailed information about financial instruments [line items]      
Estimated percentage of jet fuel expenses covered by hedging contracts as of reporting date   85.00%  
Estimated percentage of carbon emission rights in next financial year covered by hedging contracts as of reporting date 100.00%    
Carbon price risk | Cash Flow Hedges | European Union Allowance (EUA), carbon rights      
Disclosure of detailed information about financial instruments [line items]      
Average price of hedging instrument | € / Right 75 65  
Carbon price risk | Cash Flow Hedges | United Kingdom Allowance (UKA), carbon rights      
Disclosure of detailed information about financial instruments [line items]      
Average price of hedging instrument | £ / Right 50 58