v3.26.1
Borrowings - Bonds and Own shares (Details)
€ in Millions, ¥ in Billions, £ in Billions, kr in Billions, SFr in Billions, $ in Billions, $ in Billions, $ in Billions
12 Months Ended
Mar. 31, 2026
EUR (€)
shares
Mar. 31, 2026
USD ($)
shares
Mar. 31, 2026
GBP (£)
shares
Mar. 31, 2026
NOK (kr)
shares
Mar. 31, 2025
EUR (€)
shares
Mar. 31, 2026
USD ($)
Mar. 31, 2026
GBP (£)
Mar. 31, 2026
CHF (SFr)
Mar. 31, 2026
HKD ($)
Mar. 31, 2026
AUD ($)
Mar. 31, 2026
JPY (¥)
Liquidity and capital resources                      
Notional amount € 18,786       € 22,628            
Top of range [member]                      
Liquidity and capital resources                      
Treasury shares | shares 2,122,987,551 2,122,987,551 2,122,987,551 2,122,987,551 2,305,697,477            
Percentage of issued share capital held as treasury shares 8.00% 8.00% 8.00% 8.00% 8.20%            
Bonds                      
Liquidity and capital resources                      
Notional amount of borrowings outstanding € 33,000                    
Bonds | United States of America, Dollars                      
Liquidity and capital resources                      
Bonds issued | $           $ 16.0          
Nominal values of bonds re-purchased 2,100 $ 2.5                  
Bonds | Euro                      
Liquidity and capital resources                      
Bonds issued 15,400                    
Nominal values of bonds matured 1,300                    
Nominal values of bonds re-purchased 1,100                    
Bonds | Sterling                      
Liquidity and capital resources                      
Bonds issued | £             £ 2.7        
Nominal values of bonds matured 200   £ 0.2                
Nominal values of bonds re-purchased 1,900   £ 1.7                
Bonds | Australia, Dollars                      
Liquidity and capital resources                      
Bonds issued | $                   $ 0.3  
Bonds | Hong Kong, Dollars                      
Liquidity and capital resources                      
Bonds issued | $                 $ 1.8    
Bonds | Norway, Krone                      
Liquidity and capital resources                      
Nominal values of bonds matured € 20,000     kr 0.2              
Bonds | Switzerland, Francs                      
Liquidity and capital resources                      
Bonds issued | SFr               SFr 0.2      
Bonds | Japan, Yen                      
Liquidity and capital resources                      
Bonds issued | ¥                     ¥ 10.0
Bonds | Minimum.                      
Liquidity and capital resources                      
Borrowing interest rate 50000000000.00001%       50000000000.00001% 50000000000.00001% 50000000000.00001% 50000000000.00001% 50000000000.00001% 50000000000.00001% 50000000000.00001%
Bonds | Top of range [member]                      
Liquidity and capital resources                      
Borrowing interest rate 800000000000.00%       800000000000.00% 800000000000.00% 800000000000.00% 800000000000.00% 800000000000.00% 800000000000.00% 800000000000.00%
Euro medium-term note programme                      
Liquidity and capital resources                      
Number of note programmes 2 2 2 2              
Euro medium-term note programme | Euro                      
Liquidity and capital resources                      
Cash raised from bonds issued € 4,800                    
Euro medium-term note programme, one                      
Liquidity and capital resources                      
Notional amount 30,000                    
Euro medium-term note programme, one | Sterling                      
Liquidity and capital resources                      
Cash raised from bonds issued | £     £ 0.5                
Euro medium-term note programme, two                      
Liquidity and capital resources                      
Notional amount 30,000                    
Euro medium-term note programme, two | Euro                      
Liquidity and capital resources                      
Cash raised from bonds issued € 600