Employee Benefits - Weighted Average Assumptions Used to Determine Postretirement Benefit Expense and Obligation (Detail)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Liability [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.90%	2.60%
Current medical cost trend rate	6.75%	7.00%
Ultimate medical cost trend rate	4.75%	4.75%
Expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.60%	3.30%
Current medical cost trend rate	7.00%	7.25%
Ultimate medical cost trend rate	4.75%	4.75%

The current medical cost trend rate utilized to determine postretirement benefit expense.

No definition available.

Name:	iff_DefinedBenefitPlanCurrentMedicalCareCostTrendRate
Namespace Prefix:	iff_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Ultimate trend rate for health care cost for defined benefit postretirement plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_LiabilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=iff_ExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: