v3.25.4
Share-based compensation - Performance shares (Detail) - Performance share plans
 12 Months Ended
Dec. 31, 2025
shares
€ / shares
Dec. 31, 2025
shares
$ / shares
Dec. 31, 2024
shares
€ / shares
Dec. 31, 2024
shares
$ / shares
EUR        
Share-based compensation [Line Items]        
Number of other equity instruments outstanding in share-based payment arrangement at beginning of period (in shares) 6,466,838 6,466,838 5,392,035 5,392,035
Weighted average exercise price of other equity instruments outstanding in share-based payment arrangement at beginning of period (in euros per share) | € / shares € 24.41   € 27.22  
Number of other equity instruments granted in share-based payment arrangement (in shares) 1,994,246 1,994,246 2,265,462 2,265,462
Weighted average exercise price of other equity instruments granted in share-based payment arrangement (in euros per share) | € / shares € 21.94   € 28.94  
Notional Dividends (in shares) 269,210 269,210 218,782 218,782
Weighted average exercise price notional dividends (in euros per share) | € / shares € 24.63   € 24.35  
Number of other equity instruments exercised or vested in share-based payment arrangement (in shares) (333,321) (333,321) (169,524) (169,524)
Weighted average exercise price of other equity instruments exercised or vested in share-based payment arrangement (in euros per share) | € / shares € 20.73   € 50.30  
Number of other equity instruments forfeited in share-based payment arrangement (in shares) (336,681) (336,681) (451,052) (451,052)
Weighted average exercise price of other equity instruments forfeited in share-based payment arrangement (in euros per share) | € / shares € 24.93   € 25.07  
Number of other equity instruments adjusted quantity (in shares) (1,801,626) (1,801,626) (788,865) (788,865)
Weighted average exercise price of other equity instruments adjusted quantity (in euros per share) | € / shares € 20.52   € 50.65  
Number of other equity instruments outstanding in share-based payment arrangement at end of period (in shares) 6,258,667 6,258,667 6,466,838 6,466,838
Weighted average exercise price of other equity instruments outstanding in share-based payment arrangement at end of period (in euros per share) | € / shares € 24.92   € 24.41  
US Dollar        
Share-based compensation [Line Items]        
Number of other equity instruments outstanding in share-based payment arrangement at beginning of period (in shares) 4,190,628 4,190,628 3,261,048 3,261,048
Weighted average exercise price of other equity instruments outstanding in share-based payment arrangement at beginning of period (in euros per share) | $ / shares   $ 26.89   $ 29.73
Number of other equity instruments granted in share-based payment arrangement (in shares) 1,522,255 1,522,255 1,733,891 1,733,891
Weighted average exercise price of other equity instruments granted in share-based payment arrangement (in euros per share) | $ / shares   $ 24.81   $ 31.07
Notional Dividends (in shares) 187,657 187,657 142,892 142,892
Weighted average exercise price notional dividends (in euros per share) | $ / shares   $ 27.25   $ 26.85
Number of other equity instruments exercised or vested in share-based payment arrangement (in shares) (166,326) (166,326) (80,151) (80,151)
Weighted average exercise price of other equity instruments exercised or vested in share-based payment arrangement (in euros per share) | $ / shares   $ 21.98   $ 61.37
Number of other equity instruments forfeited in share-based payment arrangement (in shares) (525,643) (525,643) (489,195) (489,195)
Weighted average exercise price of other equity instruments forfeited in share-based payment arrangement (in euros per share) | $ / shares   $ 27.08   $ 28.35
Number of other equity instruments adjusted quantity (in shares) (942,807) (942,807) (377,857) (377,857)
Weighted average exercise price of other equity instruments adjusted quantity (in euros per share) | $ / shares   $ 21.98   $ 61.37
Number of other equity instruments outstanding in share-based payment arrangement at end of period (in shares) 4,265,764 4,265,764 4,190,628 4,190,628
Weighted average exercise price of other equity instruments outstanding in share-based payment arrangement at end of period (in euros per share) | $ / shares   $ 27.42   $ 26.89