Restructuring and Other Charges, Net - Additional Information (Detail) - IFF Productivity Program $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2025 USD ($)	Mar. 31, 2025 USD ($)
Restructuring Cost and Reserve [Line Items]
Additional Charges (Reversals), Net	$ 17
Employee Severance
Restructuring Cost and Reserve [Line Items]
Additional Charges (Reversals), Net	17
Restructuring costs incurred		$ 20
Fixed Asset Write Down
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred		20
Minimum \| Nourish, Health And Biosciences, And Scent
Restructuring Cost and Reserve [Line Items]
Restructuring costs expected	50	50
Maximum \| Nourish, Health And Biosciences, And Scent
Restructuring Cost and Reserve [Line Items]
Restructuring costs expected	$ 70	$ 70

Amount expected to be recognized in earnings for the specified restructuring cost.

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Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

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