v3.26.3
STOCKHOLDERS' EQUITY Part 1 (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Dec. 31, 2024
Stockholders' Equity Note [Abstract]                
Dividends, Per Share $ 0.84 $ 0.83 $ 2.52 $ 2.49        
Stockholders' Equity Attributable to Parent $ 6,276   $ 6,276     $ 5,961    
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest 6,335 $ 5,865 6,335 $ 5,865 $ 6,175 6,037 $ 5,906 $ 5,852
Net earnings attributable to Eastman 252 69 542 391        
Net earnings attributable to noncontrolling interest 1 0 2 1        
Net earnings including noncontrolling interest 253 69 544 392        
Cash dividends declared (96) (95) (290) (287)        
Other Comprehensive Income (Loss) 8 22 8 (17)        
Share-based Compensation Expense 16 13 62 38        
Stock Option Exercises     2 2        
Other (21) 0 (25) (12)        
Share Repurchases   (50)   (100)        
Distributions to Noncontrolling Interest     (3) (3)        
Noncontrolling interest 59 72 59 72 79 76 71 73
Common Stock [Member]                
Stockholders' Equity Attributable to Parent 2 2 2 2 2 2 2 2
Net earnings attributable to Eastman 0 0 0 0        
Cash dividends declared 0 0 0 0        
Other Comprehensive Income (Loss) 0 0 0 0        
Share-based Compensation Expense 0 0 0 0        
Stock Option Exercises     0 0        
Other 0 0 0 0        
Share Repurchases   0   0        
Distributions to Noncontrolling Interest     0 0        
Additional Paid-in Capital [Member]                
Stockholders' Equity Attributable to Parent 2,555 2,491 2,555 2,491 2,539 2,500 2,478 2,463
Net earnings attributable to Eastman 0 0 0 0        
Cash dividends declared 0 0 0 0        
Other Comprehensive Income (Loss) 0 0 0 0        
Share-based Compensation Expense 16 13 62 38        
Stock Option Exercises     2 2        
Other 0 0 (9) (12)        
Share Repurchases   0   0        
Distributions to Noncontrolling Interest     0 0        
Retained Earnings [Member]                
Stockholders' Equity Attributable to Parent 10,357 10,117 10,357 10,117 10,201 10,105 10,143 10,013
Net earnings attributable to Eastman 252 69 542 391        
Cash dividends declared (96) (95) (290) (287)        
Other Comprehensive Income (Loss) 0 0 0 0        
Share-based Compensation Expense 0 0 0 0        
Stock Option Exercises     0 0        
Other 0 0 0 0        
Share Repurchases   0   0        
Distributions to Noncontrolling Interest     0 0        
Accumulated Other Comprehensive Income (Loss) [Member]                
Stockholders' Equity Attributable to Parent (152) (331) (152) (331) (160) (160) (353) (314)
Net earnings attributable to Eastman 0 0 0 0        
Cash dividends declared 0 0 0 0        
Other Comprehensive Income (Loss) 8 22 8 (17)        
Share-based Compensation Expense 0 0 0 0        
Stock Option Exercises     0 0        
Other 0 0 0 0        
Share Repurchases   0   0        
Distributions to Noncontrolling Interest     0 0        
Treasury Stock, Common                
Stockholders' Equity Attributable to Parent (6,486) (6,486) (6,486) (6,486) (6,486) (6,486) (6,435) (6,385)
Net earnings attributable to Eastman 0 0 0 0        
Cash dividends declared 0 0 0 0        
Other Comprehensive Income (Loss) 0 0 0 0        
Share-based Compensation Expense 0 0 0 0        
Stock Option Exercises     0 0        
Other 0 (1) 0 (1)        
Share Repurchases   (50)   (100)        
Distributions to Noncontrolling Interest     0 0        
Parent [Member]                
Stockholders' Equity Attributable to Parent 6,276 5,793 6,276 5,793 $ 6,096 $ 5,961 $ 5,835 $ 5,779
Net earnings attributable to Eastman 252 69 542 391        
Cash dividends declared (96) (95) (290) (287)        
Other Comprehensive Income (Loss) 8 22 8 (17)        
Share-based Compensation Expense 16 13 62 38        
Stock Option Exercises     2 2        
Other 0 (1) (9) (13)        
Share Repurchases   (50)   (100)        
Distributions to Noncontrolling Interest     0 0        
Noncontrolling Interest [Member]                
Net earnings attributable to noncontrolling interest 1 0 2 1        
Cash dividends declared 0 0 0 0        
Other Comprehensive Income (Loss) 0 0 0 0        
Share-based Compensation Expense 0 0 0 0        
Stock Option Exercises     0 0        
Other (21) 1 (16) 1        
Share Repurchases   $ 0   0        
Distributions to Noncontrolling Interest     (3) $ (3)        
Payments to Noncontrolling Interests $ 20   $ 20