v3.25.4
Details of treasury and other financial risks - Currency risk narrative (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2025
EUR (€)
Dec. 31, 2024
EUR (€)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2023
EUR (€)
Dec. 31, 2022
EUR (€)
Details of treasury and other financial risks [Line Items]            
Hedge tenor of net anticipated exposure 15 months          
Net anticipated exposures hedge layer size 8.00%          
Group equity € 10,990,000,000 € 12,043,000,000     € 12,061,000,000 € 13,283,000,000
Net fair value of transactional hedges 47,000,000          
Change in the value of transactional hedges following a 10% increase in the value of a currency against EUR 104,000,000          
Impact on income statement following a change in the value of transactional hedges due to 10% increase in the value of the EUR against all currencies 48,000,000          
Impact on equity following a change in the value of transactional hedges due to 10% increase in the value of the EUR against all currencies 55,000,000          
Other comprehensive income, before tax, exchange differences on translation of foreign operations 1,641,000,000          
Change in currency translation reserve following 10% decrease USD against EUR 1,012,000,000          
Change in currency translation reserve following 10% increase USD against EUR 1,236,000,000          
External bond funding for a nominal value designated as net investment hedges | $     $ 1,331 $ 1,466    
External bond funding book value designated as net investment hedges 1,135,000,000 1,408,000,000        
Gains (losses) on hedges of net investments in foreign operations, before tax (151,000,000) 82,000,000        
Gain (loss) on hedge ineffectiveness recognised in profit or loss 0 0        
Change in the value of derivatives following a 10% increase in the value of the EUR against all currencies 26,000,000 106,000,000        
US Dollar            
Details of treasury and other financial risks [Line Items]            
Change in the value of derivatives following a 10% increase in the value of the EUR against all currencies   50,000,000        
Change in the value of derivatives following a 10% increase in the value of a currency against EUR 1,000,000          
Cash flow hedges            
Details of treasury and other financial risks [Line Items]            
Gain (loss) on hedge ineffectiveness 500,000 0        
Cash flow hedges            
Details of treasury and other financial risks [Line Items]            
Group equity 33,000,000 1,000,000     € 6,000,000 € (2,000,000)
Change in value of forward elements of forward contracts and time value of options            
Details of treasury and other financial risks [Line Items]            
Group equity € 29,000,000 € 29,000,000