v3.25.1
Capital and financial risk management - Risk management strategy of hedge relationships - Tabular disclosure (Details)
$ in Millions
12 Months Ended
Mar. 31, 2025
EUR (€)
Mar. 31, 2025
EUR (€)
$ / EUR
Mar. 31, 2025
EUR (€)
$ / EUR
Mar. 31, 2025
EUR (€)
SFr / EUR
Mar. 31, 2025
EUR (€)
£ / EUR
Mar. 31, 2025
EUR (€)
$ / EUR
Mar. 31, 2025
EUR (€)
¥ / EUR
Mar. 31, 2025
EUR (€)
kr / EUR
Mar. 31, 2025
EUR (€)
R / EUR
Mar. 31, 2025
EUR (€)
₺ / EUR
Mar. 31, 2025
EUR (€)
₺ / USD
Mar. 31, 2024
EUR (€)
Mar. 31, 2024
EUR (€)
$ / EUR
Mar. 31, 2024
EUR (€)
$ / EUR
Mar. 31, 2024
EUR (€)
SFr / EUR
Mar. 31, 2024
EUR (€)
£ / EUR
Mar. 31, 2024
EUR (€)
$ / EUR
Mar. 31, 2024
EUR (€)
¥ / EUR
Mar. 31, 2024
EUR (€)
kr / EUR
Mar. 31, 2024
EUR (€)
R / EUR
Mar. 31, 2024
EUR (€)
₺ / EUR
Mar. 31, 2024
EUR (€)
₺ / USD
Mar. 31, 2025
USD ($)
Mar. 31, 2024
USD ($)
Risk management strategy of hedge relationships                                                
Nominal value € 22,628,000,000 € 22,628,000,000 € 22,628,000,000 € 22,628,000,000 € 22,628,000,000 € 22,628,000,000 € 22,628,000,000 € 22,628,000,000 € 22,628,000,000 € 22,628,000,000 € 22,628,000,000 € 24,783,000,000 € 24,783,000,000 € 24,783,000,000 € 24,783,000,000 € 24,783,000,000 € 24,783,000,000 € 24,783,000,000 € 24,783,000,000 € 24,783,000,000 € 24,783,000,000 € 24,783,000,000    
Carrying value assets 2,484,000,000 2,484,000,000 2,484,000,000 2,484,000,000 2,484,000,000 2,484,000,000 2,484,000,000 2,484,000,000 2,484,000,000 2,484,000,000 2,484,000,000 3,010,000,000 3,010,000,000 3,010,000,000 3,010,000,000 3,010,000,000 3,010,000,000 3,010,000,000 3,010,000,000 3,010,000,000 3,010,000,000 3,010,000,000    
Carrying value liabilities 611,000,000 611,000,000 611,000,000 611,000,000 611,000,000 611,000,000 611,000,000 611,000,000 611,000,000 611,000,000 611,000,000 652,000,000 652,000,000 652,000,000 652,000,000 652,000,000 652,000,000 652,000,000 652,000,000 652,000,000 652,000,000 652,000,000    
Other comprehensive income                                                
Opening balance (28,202,000,000)                     (30,262,000,000)                        
Closing balance (28,886,000,000)                     (28,202,000,000)                        
Additional losses from previous designated hedge relationships included in carrying value of bonds 457,000,000 457,000,000 457,000,000 457,000,000 457,000,000 457,000,000 457,000,000 457,000,000 457,000,000 € 457,000,000 € 457,000,000 710,000,000 710,000,000 710,000,000 710,000,000 710,000,000 710,000,000 710,000,000 710,000,000 710,000,000 € 710,000,000 € 710,000,000    
Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance 345,000,000                     (1,892,000,000)                        
(Gain)/Loss deferred to OCI 134,000,000                     1,983,000,000                        
Gain/(Loss) recycled to financing costs (197,000,000)                     254,000,000                        
Closing balance 408,000,000                     345,000,000                        
Foreign exchange risk                                                
Other comprehensive income                                                
Average FX rate                   0 0                   29.68 30.15    
Foreign exchange risk | Euro to Turkish Lira forward exchange contracts                                                
Risk management strategy of hedge relationships                                                
Nominal value 0 0 0 0 0 0 0 0 0 € 0 € 0 166,000,000 166,000,000 166,000,000 166,000,000 166,000,000 166,000,000 166,000,000 166,000,000 166,000,000 € 166,000,000 € 166,000,000    
Foreign exchange risk | USD to Turkish Lira forward exchange contracts                                                
Risk management strategy of hedge relationships                                                
Nominal value                       121,000,000 121,000,000 121,000,000 121,000,000 121,000,000 121,000,000 121,000,000 121,000,000 121,000,000 121,000,000 121,000,000 $ 0 $ 130
Cash flow hedges                                                
Other comprehensive income                                                
Loss from foreign currency basis outside the cash flow and net investment hedge relationships 200,000,000                     251,000,000                        
Hedge ineffectiveness 28,000,000                     67,000,000                        
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | US dollar bonds                                                
Risk management strategy of hedge relationships                                                
Nominal value 16,097,000,000 16,097,000,000 16,097,000,000 16,097,000,000 16,097,000,000 16,097,000,000 16,097,000,000 16,097,000,000 16,097,000,000 16,097,000,000 16,097,000,000 16,756,000,000 16,756,000,000 16,756,000,000 16,756,000,000 16,756,000,000 16,756,000,000 16,756,000,000 16,756,000,000 16,756,000,000 16,756,000,000 16,756,000,000    
Carrying value assets 2,245,000,000 2,245,000,000 2,245,000,000 2,245,000,000 2,245,000,000 2,245,000,000 2,245,000,000 2,245,000,000 2,245,000,000 2,245,000,000 2,245,000,000 2,689,000,000 2,689,000,000 2,689,000,000 2,689,000,000 2,689,000,000 2,689,000,000 2,689,000,000 2,689,000,000 2,689,000,000 2,689,000,000 2,689,000,000    
Carrying value liabilities € 138,000,000 € 138,000,000 € 138,000,000 € 138,000,000 € 138,000,000 € 138,000,000 € 138,000,000 € 138,000,000 € 138,000,000 € 138,000,000 € 138,000,000 € 188,000,000 € 188,000,000 € 188,000,000 € 188,000,000 € 188,000,000 € 188,000,000 € 188,000,000 € 188,000,000 € 188,000,000 € 188,000,000 € 188,000,000    
Other comprehensive income                                                
Average FX rate | $ / EUR   1.15                     1.18                      
Average euro interest rate 3.51% 3.51% 3.51% 3.51% 3.51% 3.51% 3.51% 3.51% 3.51% 3.51% 3.51% 3.29% 3.29% 3.29% 3.29% 3.29% 3.29% 3.29% 3.29% 3.29% 3.29% 3.29% 3.51% 3.29%
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | US dollar bonds | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € (810,000,000)                     € (2,709,000,000)                        
(Gain)/Loss deferred to OCI 307,000,000                     (1,775,000,000)                        
Gain/(Loss) recycled to financing costs (56,000,000)                     (124,000,000)                        
Closing balance (1,061,000,000)                     (810,000,000)                        
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Australian dollar bonds                                                
Risk management strategy of hedge relationships                                                
Nominal value 163,000,000 € 163,000,000 € 163,000,000 € 163,000,000 € 163,000,000 € 163,000,000 € 163,000,000 € 163,000,000 € 163,000,000 € 163,000,000 € 163,000,000 288,000,000 € 288,000,000 € 288,000,000 € 288,000,000 € 288,000,000 € 288,000,000 € 288,000,000 € 288,000,000 € 288,000,000 € 288,000,000 € 288,000,000    
Carrying value liabilities € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 2,000,000 € 2,000,000 € 2,000,000 € 2,000,000 € 2,000,000 € 2,000,000 € 2,000,000 € 2,000,000 € 2,000,000 € 2,000,000 € 2,000,000    
Other comprehensive income                                                
Average FX rate | $ / EUR     1.56                     1.56                    
Average euro interest rate 1.58% 1.58% 1.58% 1.58% 1.58% 1.58% 1.58% 1.58% 1.58% 1.58% 1.58% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.58% 1.57%
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Australian dollar bonds | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € (13,000,000)                     € (21,000,000)                        
(Gain)/Loss deferred to OCI (14,000,000)                     (14,000,000)                        
Gain/(Loss) recycled to financing costs 2,000,000                     6,000,000                        
Closing balance (1,000,000)                     (13,000,000)                        
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Swiss franc bonds                                                
Risk management strategy of hedge relationships                                                
Nominal value 204,000,000 € 204,000,000 € 204,000,000 € 204,000,000 € 204,000,000 € 204,000,000 € 204,000,000 € 204,000,000 € 204,000,000 € 204,000,000 € 204,000,000 624,000,000 € 624,000,000 € 624,000,000 € 624,000,000 € 624,000,000 € 624,000,000 € 624,000,000 € 624,000,000 € 624,000,000 € 624,000,000 € 624,000,000    
Carrying value assets € 37,000,000 € 37,000,000 € 37,000,000 € 37,000,000 € 37,000,000 € 37,000,000 € 37,000,000 € 37,000,000 € 37,000,000 € 37,000,000 € 37,000,000 € 80,000,000 € 80,000,000 € 80,000,000 € 80,000,000 € 80,000,000 € 80,000,000 € 80,000,000 € 80,000,000 € 80,000,000 € 80,000,000 € 80,000,000    
Other comprehensive income                                                
Average FX rate | SFr / EUR       1.08                     1.08                  
Average euro interest rate 1.53% 1.53% 1.53% 1.53% 1.53% 1.53% 1.53% 1.53% 1.53% 1.53% 1.53% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.57% 1.53% 1.57%
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Swiss franc bonds | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € (10,000,000)                     € (3,000,000)                        
(Gain)/Loss deferred to OCI 23,000,000                     22,000,000                        
Gain/(Loss) recycled to financing costs (24,000,000)                     (15,000,000)                        
Closing balance (9,000,000)                     (10,000,000)                        
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Pound sterling bonds                                                
Risk management strategy of hedge relationships                                                
Nominal value 4,642,000,000 € 4,642,000,000 € 4,642,000,000 € 4,642,000,000 € 4,642,000,000 € 4,642,000,000 € 4,642,000,000 € 4,642,000,000 € 4,642,000,000 € 4,642,000,000 € 4,642,000,000 4,771,000,000 € 4,771,000,000 € 4,771,000,000 € 4,771,000,000 € 4,771,000,000 € 4,771,000,000 € 4,771,000,000 € 4,771,000,000 € 4,771,000,000 € 4,771,000,000 € 4,771,000,000    
Carrying value assets 58,000,000 58,000,000 58,000,000 58,000,000 58,000,000 58,000,000 58,000,000 58,000,000 58,000,000 58,000,000 58,000,000 45,000,000 45,000,000 45,000,000 45,000,000 45,000,000 45,000,000 45,000,000 45,000,000 45,000,000 45,000,000 45,000,000    
Carrying value liabilities € 444,000,000 € 444,000,000 € 444,000,000 € 444,000,000 € 444,000,000 € 444,000,000 € 444,000,000 € 444,000,000 € 444,000,000 € 444,000,000 € 444,000,000 € 362,000,000 € 362,000,000 € 362,000,000 € 362,000,000 € 362,000,000 € 362,000,000 € 362,000,000 € 362,000,000 € 362,000,000 € 362,000,000 € 362,000,000    
Other comprehensive income                                                
Average FX rate | £ / EUR         0.86                     0.86                
Average euro interest rate 3.84% 3.84% 3.84% 3.84% 3.84% 3.84% 3.84% 3.84% 3.84% 3.84% 3.84% 4.05% 4.05% 4.05% 4.05% 4.05% 4.05% 4.05% 4.05% 4.05% 4.05% 4.05% 3.84% 4.05%
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Pound sterling bonds | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € 333,000,000                     € (37,000,000)                        
(Gain)/Loss deferred to OCI (86,000,000)                     (244,000,000)                        
Gain/(Loss) recycled to financing costs (70,000,000)                     (126,000,000)                        
Closing balance 489,000,000                     333,000,000                        
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Hong Kong dollar bonds                                                
Risk management strategy of hedge relationships                                                
Nominal value 216,000,000 € 216,000,000 € 216,000,000 € 216,000,000 € 216,000,000 € 216,000,000 € 216,000,000 € 216,000,000 € 216,000,000 € 216,000,000 € 216,000,000 233,000,000 € 233,000,000 € 233,000,000 € 233,000,000 € 233,000,000 € 233,000,000 € 233,000,000 € 233,000,000 € 233,000,000 € 233,000,000 € 233,000,000    
Carrying value assets € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000 € 20,000,000    
Other comprehensive income                                                
Average FX rate | $ / EUR           9.14                     9.08              
Average euro interest rate 1.62% 1.62% 1.62% 1.62% 1.62% 1.62% 1.62% 1.62% 1.62% 1.62% 1.62% 1.92% 1.92% 1.92% 1.92% 1.92% 1.92% 1.92% 1.92% 1.92% 1.92% 1.92% 1.62% 1.92%
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Hong Kong dollar bonds | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € 0                     € (5,000,000)                        
(Gain)/Loss deferred to OCI 4,000,000                     (2,000,000)                        
Gain/(Loss) recycled to financing costs (3,000,000)                     (3,000,000)                        
Closing balance (1,000,000)                     0                        
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Japanese yen bonds                                                
Risk management strategy of hedge relationships                                                
Nominal value 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000 € 78,000,000    
Carrying value liabilities € 14,000,000 € 14,000,000 € 14,000,000 € 14,000,000 € 14,000,000 € 14,000,000 € 14,000,000 € 14,000,000 € 14,000,000 € 14,000,000 € 14,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000 € 11,000,000    
Other comprehensive income                                                
Average FX rate | ¥ / EUR             128.53                     128.53            
Average euro interest rate 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47% 2.47%
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Japanese yen bonds | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € (6,000,000)                     € (12,000,000)                        
(Gain)/Loss deferred to OCI (2,000,000)                     (15,000,000)                        
Gain/(Loss) recycled to financing costs (1,000,000)                     9,000,000                        
Closing balance (3,000,000)                     (6,000,000)                        
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Norwegian krona bonds                                                
Risk management strategy of hedge relationships                                                
Nominal value 25,000,000 € 25,000,000 € 25,000,000 € 25,000,000 € 25,000,000 € 25,000,000 € 25,000,000 € 25,000,000 € 25,000,000 € 25,000,000 € 25,000,000 241,000,000 € 241,000,000 € 241,000,000 € 241,000,000 € 241,000,000 € 241,000,000 € 241,000,000 € 241,000,000 € 241,000,000 € 241,000,000 € 241,000,000    
Carrying value liabilities € 4,000,000 € 4,000,000 € 4,000,000 € 4,000,000 € 4,000,000 € 4,000,000 € 4,000,000 € 4,000,000 € 4,000,000 € 4,000,000 € 4,000,000 € 47,000,000 € 47,000,000 € 47,000,000 € 47,000,000 € 47,000,000 € 47,000,000 € 47,000,000 € 47,000,000 € 47,000,000 € 47,000,000 € 47,000,000    
Other comprehensive income                                                
Average FX rate | kr / EUR               9.25                     9.15          
Average euro interest rate 0.37% 0.37% 0.37% 0.37% 0.37% 0.37% 0.37% 0.37% 0.37% 0.37% 0.37% 1.12% 1.12% 1.12% 1.12% 1.12% 1.12% 1.12% 1.12% 1.12% 1.12% 1.12% 0.37% 1.12%
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Norwegian krona bonds | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € (5,000,000)                     € (12,000,000)                        
(Gain)/Loss deferred to OCI (3,000,000)                     (13,000,000)                        
Gain/(Loss) recycled to financing costs (2,000,000)                     6,000,000                        
Closing balance 0                     (5,000,000)                        
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Foreign exchange forwards                                                
Risk management strategy of hedge relationships                                                
Nominal value 0 € 0 € 0 € 0 € 0 € 0 € 0 € 0 € 0 € 0 € 0 287,000,000 € 287,000,000 € 287,000,000 € 287,000,000 € 287,000,000 € 287,000,000 € 287,000,000 € 287,000,000 € 287,000,000 € 287,000,000 € 287,000,000    
Carrying value liabilities € 0 € 0 € 0 € 0 € 0 € 0 € 0 € 0 € 0 € 0 € 0 € 42,000,000 € 42,000,000 € 42,000,000 € 42,000,000 € 42,000,000 € 42,000,000 € 42,000,000 € 42,000,000 € 42,000,000 € 42,000,000 € 42,000,000    
Other comprehensive income                                                
Average FX rate 0                     29.88                        
Average euro interest rate 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%                       0.00%  
Cash flow hedges | Foreign exchange risk | Cross currency and foreign exchange swaps | Foreign exchange forwards | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € (42,000,000)                     € (34,000,000)                        
(Gain)/Loss deferred to OCI 1,000,000                     15,000,000                        
Gain/(Loss) recycled to financing costs (43,000,000)                     (7,000,000)                        
Closing balance € 0                     € (42,000,000)                        
Cash flow hedges | Foreign currency and interest rate risk | Currency swap contract | US dollar bonds                                                
Other comprehensive income                                                
Average FX rate | $ / EUR   0                     0                      
Average euro interest rate 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%
Cash flow hedges | Foreign currency and interest rate risk | Currency swap contract | US dollar bonds | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € 0                     € (11,000,000)                        
(Gain)/Loss deferred to OCI 0                     (11,000,000)                        
Closing balance                       0                        
Net investment hedge                                                
Other comprehensive income                                                
Hedge ineffectiveness 0                     0                        
Gain from foreign currency basis outside the cash flow and net investment hedge relationships 1,000,000                     10,000,000                        
Net investment hedge | Foreign exchange risk | Cross currency and foreign exchange swaps | South African rand investment                                                
Risk management strategy of hedge relationships                                                
Nominal value 1,203,000,000 € 1,203,000,000 € 1,203,000,000 € 1,203,000,000 € 1,203,000,000 € 1,203,000,000 € 1,203,000,000 € 1,203,000,000 € 1,203,000,000 € 1,203,000,000 € 1,203,000,000 1,505,000,000 € 1,505,000,000 € 1,505,000,000 € 1,505,000,000 € 1,505,000,000 € 1,505,000,000 € 1,505,000,000 € 1,505,000,000 € 1,505,000,000 € 1,505,000,000 € 1,505,000,000    
Carrying value assets € 124,000,000 € 124,000,000 € 124,000,000 € 124,000,000 € 124,000,000 € 124,000,000 € 124,000,000 € 124,000,000 € 124,000,000 € 124,000,000 € 124,000,000 € 176,000,000 € 176,000,000 € 176,000,000 € 176,000,000 € 176,000,000 € 176,000,000 € 176,000,000 € 176,000,000 € 176,000,000 € 176,000,000 € 176,000,000    
Other comprehensive income                                                
Average FX rate | R / EUR                 17.62                     17.81        
Average euro interest rate 2.76% 2.76% 2.76% 2.76% 2.76% 2.76% 2.76% 2.76% 2.76% 2.76% 2.76% 2.19% 2.19% 2.19% 2.19% 2.19% 2.19% 2.19% 2.19% 2.19% 2.19% 2.19% 2.76% 2.19%
Net investment hedge | Foreign exchange risk | Cross currency and foreign exchange swaps | South African rand investment | Reserves of cash flow hedges and net investment hedges                                                
Other comprehensive income                                                
Opening balance € 898,000,000                     € 952,000,000                        
(Gain)/Loss deferred to OCI (96,000,000)                     54,000,000                        
Closing balance € 994,000,000                     € 898,000,000