Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 17
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-17

+ Details

Name:	us-gaap_PaymentsForRestructuring
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount 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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482047/420-10-45-3

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-1

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 5.P.4(b)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

+ Details

Name:	us-gaap_RestructuringReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

+ Details

Name:	us-gaap_RestructuringReserveAccrualAdjustment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_RestructuringReserveRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of decrease in the reserve for full or partial settlement through consideration other than cash.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482017/420-10-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4(b)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479823/420-10-S99-2

+ Details

Name:	us-gaap_RestructuringReserveSettledWithoutCash2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_BusinessAcquisitionAxis=iff_NutritionBiosciencesIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_EmployeeSeveranceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringCostAndReserveAxis=us-gaap_OtherRestructuringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=iff_FrutaromIntegrationInitiativeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RestructuringPlanAxis=iff_A2023RestructuringProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=iff_NourishMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=iff_ScentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=iff_HealthBiosciencesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=iff_PharmaSolutionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Restructuring and Other Charges, Net - Changes in Employee-Related Restructuring Liabilities (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Restructuring Reserve [Roll Forward]
Beginning Balance		$ 15		$ 15
Additional Charges (Reversals), Net				61
Non-Cash Charges				(2)
Additional charges, net	$ 2		$ (4)	61	$ 5
Payments				(49)
Ending Balance	25			25
Nutrition & Biosciences, Inc
Restructuring Reserve [Roll Forward]
Additional Charges (Reversals), Net				2
Additional charges, net				47
Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance		1		1
Additional Charges (Reversals), Net				(1)
Non-Cash Charges				0
Payments				0
Ending Balance	0			0
Employee Severance \| Nutrition & Biosciences, Inc
Restructuring Reserve [Roll Forward]
Beginning Balance		9		9
Additional Charges (Reversals), Net				0
Non-Cash Charges				0
Payments				(8)
Ending Balance	1			1
Other \| Nutrition & Biosciences, Inc
Restructuring Reserve [Roll Forward]
Beginning Balance		1		1
Additional Charges (Reversals), Net				2
Non-Cash Charges				(2)
Payments				(1)
Ending Balance	0			0
Frutarom Integration Initiative
Restructuring Reserve [Roll Forward]
Additional charges, net		36
Frutarom Integration Initiative \| Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance		4		4
Additional Charges (Reversals), Net				(3)
Non-Cash Charges				0
Payments				(1)
Ending Balance	0			0
2023 Restructuring Program \| Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance		$ 0		0
Additional Charges (Reversals), Net				63
Non-Cash Charges				0
Payments				(39)
Ending Balance	24			24
Nourish
Restructuring Reserve [Roll Forward]
Additional charges, net	1		0	33	3
Scent
Restructuring Reserve [Roll Forward]
Additional charges, net	0		(5)	14	0
Health & Biosciences
Restructuring Reserve [Roll Forward]
Additional charges, net	1		1	12	2
Pharma Solutions
Restructuring Reserve [Roll Forward]
Additional charges, net	$ 0		$ 0	$ 2	$ 0