Fair Value Measurement (Details) - EBP 002 - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
EBP, Investment, Fair Value and NAV [Line Items]
Investments at fair value	$ 3,159,568	$ 2,955,313
Common stock - Eastman Chemical Company
EBP, Investment, Fair Value and NAV [Line Items]
Investments at fair value	217,000	266,000
Fair Value, Inputs, Level 1
EBP, Investment, Fair Value and NAV [Line Items]
Investments at fair value	3,159,568	2,955,313
Fair Value, Inputs, Level 1 \| Cash and Cash Equivalents
EBP, Investment, Fair Value and NAV [Line Items]
Investments at fair value	4,563	5,617
Fair Value, Inputs, Level 1 \| Common stock - Eastman Chemical Company
EBP, Investment, Fair Value and NAV [Line Items]
Investments at fair value	216,548	265,688
Fair Value, Inputs, Level 1 \| Common stock - other
EBP, Investment, Fair Value and NAV [Line Items]
Investments at fair value	124,441	121,904
Fair Value, Inputs, Level 1 \| Mutual funds
EBP, Investment, Fair Value and NAV [Line Items]
Investments at fair value	178,543	169,871
Fair Value, Inputs, Level 1 \| Collective investment trusts
EBP, Investment, Fair Value and NAV [Line Items]
Investments at fair value	2,445,950	2,213,427
Fair Value, Inputs, Level 1 \| Self-directed brokerage account
EBP, Investment, Fair Value and NAV [Line Items]
Investments at fair value	$ 189,523	$ 178,806

Fair value of investment, excluding plan interest in master trust, held by employee stock purchase, saving, or similar plan (employee benefit plan (EBP)). Includes, but is not limited to, derivative, investment measured at net asset value per share as practical expedient, and insurance contract not meeting fully-benefit responsive investment criteria.

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Name:	us-gaap-ebp_EmployeeBenefitPlanInvestmentExcludingPlanInterestInMasterTrustFairValue
Namespace Prefix:	us-gaap-ebp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant