v3.26.1
Net Income Per Share - Reconciliation of Shares Used in Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Net income (loss) available to IFF shareholders $ 169 $ (1,018)
Weighted average common shares outstanding (basic) (in shares) 256 256
Weighted average shares assuming dilution (diluted) (in shares) 257 256
Net income per share - basic (in dollars per share) $ 0.66 $ (3.98)
Net income per share - diluted (in dollars per share) $ 0.66 $ (3.98)
Stock options and restricted stock awards    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Adjustment for assumed dilution (in shares) 1 0