v3.26.1
Consolidated shareholders' equity - Summary of stock subscription option plans (Details) - Stock option plan
6 Months Ended
Jun. 30, 2026
shares
€ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Number of options, outstanding (in shares) | shares 639,194
Number of options, exercisable (in shares) | shares 639,194
From €60.00 to €70.00 per share  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Number of options, outstanding (in shares) | shares 168,784
Weighted average residual life (years) 1 year 10 months 2 days
Weighted average exercise price per share, outstanding (in euros per share) € 65.84
Number of options, exercisable (in shares) | shares 168,784
Weighted average exercise price per share, exercisable (in euros per share) € 65.84
From €70.00 to €80.00 per share  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Number of options, outstanding (in shares) | shares 213,400
Weighted average residual life (years) 2 years 10 months 2 days
Weighted average exercise price per share, outstanding (in euros per share) € 76.71
Number of options, exercisable (in shares) | shares 213,400
Weighted average exercise price per share, exercisable (in euros per share) € 76.71
From €80.00 to €90.00 per share  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Number of options, outstanding (in shares) | shares 257,010
Weighted average residual life (years) 10 months 9 days
Weighted average exercise price per share, outstanding (in euros per share) € 88.97
Number of options, exercisable (in shares) | shares 257,010
Weighted average exercise price per share, exercisable (in euros per share) € 88.97
Bottom of range | From €60.00 to €70.00 per share  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Exercise price of outstanding options (in euros per share) 60.00
Bottom of range | From €70.00 to €80.00 per share  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Exercise price of outstanding options (in euros per share) 70.00
Bottom of range | From €80.00 to €90.00 per share  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Exercise price of outstanding options (in euros per share) 80.00
Top of range | From €60.00 to €70.00 per share  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Exercise price of outstanding options (in euros per share) 70.00
Top of range | From €70.00 to €80.00 per share  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Exercise price of outstanding options (in euros per share) 80.00
Top of range | From €80.00 to €90.00 per share  
Disclosure of terms and conditions of share-based payment arrangement [line items]  
Exercise price of outstanding options (in euros per share) € 90.00