SEGMENT INFORMATION (Details) Part 1 - Segment	12 Months Ended
SEGMENT INFORMATION (Details) Part 1 - Segment	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting [Abstract]
Number of Reportable Segments	4
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Advanced Materials [Member] \| North America [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	33.00%	31.00%	32.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Advanced Materials [Member] \| Asia Pacific [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	36.00%	37.00%	35.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Advanced Materials [Member] \| EMEA [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	25.00%	26.00%	27.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Advanced Materials [Member] \| Latin America [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	6.00%	6.00%	6.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Additives And Functional Products [Member] \| North America [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	43.00%	43.00%	42.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Additives And Functional Products [Member] \| Asia Pacific [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	19.00%	21.00%	21.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Additives And Functional Products [Member] \| EMEA [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	31.00%	30.00%	31.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Additives And Functional Products [Member] \| Latin America [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	7.00%	6.00%	6.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Chemical Intermediates [Member] \| North America [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	71.00%	70.00%	71.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Chemical Intermediates [Member] \| Asia Pacific [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	7.00%	7.00%	8.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Chemical Intermediates [Member] \| EMEA [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	17.00%	18.00%	17.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Chemical Intermediates [Member] \| Latin America [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	5.00%	5.00%	4.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Fibers [Member] \| North America [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	23.00%	21.00%	21.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Fibers [Member] \| Asia Pacific [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	37.00%	36.00%	35.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Fibers [Member] \| EMEA [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	36.00%	41.00%	42.00%
Revenue, Segment Benchmark \| Geographic Concentration Risk [Member] \| Fibers [Member] \| Latin America [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	4.00%	2.00%	2.00%
Advanced Interlayers Product Line [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Advanced Materials [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	32.00%	33.00%	34.00%
Performance Films Product Line [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Advanced Materials [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	19.00%	20.00%	21.00%
Specialty Plastics Product Line [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Advanced Materials [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	49.00%	47.00%	45.00%
Care Chemicals Product LIne [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Additives And Functional Products [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	38.00%	37.00%	37.00%
Coatings and Inks Additives Product Line [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Additives And Functional Products [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	27.00%	28.00%	27.00%
Specialty Fluids Product Line [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Additives And Functional Products [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	16.00%	16.00%	18.00%
Functional Amines Product Line [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Additives And Functional Products [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	19.00%	19.00%	18.00%
Intermediates product line [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Chemical Intermediates [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	76.00%	75.00%	78.00%
Plasticizers Product Line [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Chemical Intermediates [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	24.00%	25.00%	22.00%
Acetate Tow Product Line Member \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Fibers [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	69.00%	69.00%	70.00%
Acetate Yarn [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Fibers [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	11.00%	13.00%	11.00%
Acetyl Chemical Products [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Fibers [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	14.00%	13.00%	14.00%
Nonwovens [Member] \| Revenue, Segment Benchmark \| Product Concentration Risk [Member] \| Fibers [Member]
Revenue from External Customer [Line Items]
Concentration Risk, Percentage	6.00%	5.00%	5.00%

EASTMAN CHEMICAL CO 10-K