v3.26.1
Revenue from contracts with customers - Disclosures about major customers and credit risk (Details) - EUR (€)
€ in Millions
 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales € 22,106 € 19,889
Dupixent    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 9,324 7,312
ALTUVIIIO    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 674 542
Fabrazyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 523 525
Nexviazyme/Nexviadyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 426 387
Cerezyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 352 363
Ayvakit    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 367 0
Sarclisa    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 354 276
Lantus    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 813 876
Toujeo    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 729 692
Plavix    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 440 473
Lovenox    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 364 447
Rezurock    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 296 263
Industrial sales    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 190 251
Polio/pertussis/Hib primary vaccines and boosters, incl. Heplisav-B    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 1,364 1,361
RSV vaccines (Beyfortus)    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 392 356
Meningitis, travel and endemics vaccines    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 565 609
COVID-19 and Influenza vaccines    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 121 214
Of which total launches    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 3,047 2,100
Europe    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 4,304 4,144
Europe | Dupixent    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 1,146 944
Europe | ALTUVIIIO    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 0 0
Europe | Fabrazyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 138 134
Europe | Nexviazyme/Nexviadyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 152 132
Europe | Cerezyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 126 119
Europe | Ayvakit    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 44 0
Europe | Sarclisa    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 108 83
Europe | Lantus    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 146 149
Europe | Toujeo    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 259 248
Europe | Plavix    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 40 44
Europe | Lovenox    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 202 247
Europe | Rezurock    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 36 23
Europe | Industrial sales    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 181 241
Europe | Polio/pertussis/Hib primary vaccines and boosters, incl. Heplisav-B    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 206 223
Europe | RSV vaccines (Beyfortus)    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 87 85
Europe | Meningitis, travel and endemics vaccines    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 118 96
Europe | COVID-19 and Influenza vaccines    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 33 52
Europe | Of which total launches    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 546 423
United States    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 11,633 9,535
United States | Dupixent    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 6,922 5,283
United States | ALTUVIIIO    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 576 456
United States | Fabrazyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 256 261
United States | Nexviazyme/Nexviadyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 211 195
United States | Cerezyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 86 91
United States | Ayvakit    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 322 0
United States | Sarclisa    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 132 119
United States | Lantus    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 344 395
United States | Toujeo    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 134 126
United States | Plavix    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 2 3
United States | Lovenox    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 5 9
United States | Rezurock    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 218 220
United States | Industrial sales    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 7 1
United States | Polio/pertussis/Hib primary vaccines and boosters, incl. Heplisav-B    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 487 320
United States | RSV vaccines (Beyfortus)    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 65 68
United States | Meningitis, travel and endemics vaccines    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 268 319
United States | COVID-19 and Influenza vaccines    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 16 54
United States | Of which total launches    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 1,891 1,204
Other countries    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 6,169 6,210
Other countries | Dupixent    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 1,256 1,085
Other countries | ALTUVIIIO    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 98 86
Other countries | Fabrazyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 129 130
Other countries | Nexviazyme/Nexviadyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 63 60
Other countries | Cerezyme    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 140 153
Other countries | Ayvakit    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 1 0
Other countries | Sarclisa    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 114 74
Other countries | Lantus    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 323 332
Other countries | Toujeo    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 336 318
Other countries | Plavix    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 398 426
Other countries | Lovenox    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 157 191
Other countries | Rezurock    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 42 20
Other countries | Industrial sales    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 2 9
Other countries | Polio/pertussis/Hib primary vaccines and boosters, incl. Heplisav-B    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 671 818
Other countries | RSV vaccines (Beyfortus)    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 240 203
Other countries | Meningitis, travel and endemics vaccines    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 179 194
Other countries | COVID-19 and Influenza vaccines    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales 72 108
Other countries | Of which total launches    
Disclosure of disaggregation of revenue from contracts with customers [line items]    
Net sales € 610 € 473