STOCKHOLDERS' EQUITY Part 1 (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2023
Stockholders' Equity Note [Abstract]
Dividends, Per Share	$ 0.83	$ 0.81	$ 2.49	$ 2.43
Stockholders' Equity Attributable to Parent	$ 5,771		$ 5,771		$ 5,779
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	5,843	$ 5,728	5,843	$ 5,728	5,852	$ 5,906	$ 5,699	$ 5,530
Net earnings attributable to Eastman	47	180	369	575
Net earnings attributable to noncontrolling interest	0	1	1	2
Net earnings including noncontrolling interest	47	181	370	577
Cash dividends declared	(95)	(94)	(287)	(285)
Other Comprehensive Income (Loss)	22	24	(17)	41	5
Share-based Compensation Expense	13	14	38	49
Stock Option Exercises		4	2	26
Other	0	0	(12)	(9)
Share Repurchases	(50)	(100)	(100)	(200)
Distributions to Noncontrolling Interest			(3)	(1)
Noncontrolling interest	72	74	72	74	73	71	72	72
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	0
Other	0	0	0	0
Share Repurchases	0	0	0	0
Distributions to Noncontrolling Interest			0	0
Additional Paid-in Capital [Member]
Stockholders' Equity Attributable to Parent	2,491	2,435	2,491	2,435	2,463	2,478	2,417	2,368
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	13	14	38	49
Stock Option Exercises		4	2	26
Other	0	0	(12)	(8)
Share Repurchases	0	0	0	0
Distributions to Noncontrolling Interest			0	0
Retained Earnings [Member]
Stockholders' Equity Attributable to Parent	10,095	9,780	10,095	9,780	10,013	10,143	9,694	9,490
Net earnings attributable to Eastman	47	180	369	575
Cash dividends declared	(95)	(94)	(287)	(285)
Other Comprehensive Income (Loss)	0	0	0	0
Share-based Compensation Expense	0	0	0	0
Stock Option Exercises		0	0	0
Other	0	0	0	0
Share Repurchases	0	0	0	0
Distributions to Noncontrolling Interest			0	0
Accumulated Other Comprehensive Income (Loss) [Member]
Stockholders' Equity Attributable to Parent	(331)	(278)	(331)	(278)	(314)	(353)	(302)	(319)
Net earnings attributable to Eastman	0	0	0	0
Cash dividends declared	0	0	0	0
Other Comprehensive Income (Loss)	22	24	(17)	41
Share-based Compensation Expense	0	0	0	0
Stock Option Exercises		0	0	0
Other	0	0	0	0
Share Repurchases	0	0	0	0
Distributions to Noncontrolling Interest			0	0
Treasury Stock, Common
Stockholders' Equity Attributable to Parent	(6,486)	(6,285)	(6,486)	(6,285)	(6,385)	(6,435)	(6,184)	(6,083)
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	0
Other	(1)	(1)	(1)	(2)
Share Repurchases	(50)	(100)	(100)	(200)
Distributions to Noncontrolling Interest			0	0
Parent [Member]
Stockholders' Equity Attributable to Parent	5,771	5,654	5,771	5,654	$ 5,779	$ 5,835	$ 5,627	$ 5,458
Net earnings attributable to Eastman	47	180	369	575
Cash dividends declared	(95)	(94)	(287)	(285)
Other Comprehensive Income (Loss)	22	24	(17)	41
Share-based Compensation Expense	13	14	38	49
Stock Option Exercises		4	2	26
Other	(1)	(1)	(13)	(10)
Share Repurchases	(50)	(100)	(100)	(200)
Distributions to Noncontrolling Interest			0	0
Noncontrolling Interest [Member]
Net earnings attributable to noncontrolling interest	0	1	1	2
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	0
Other	1	1	1	1
Share Repurchases	$ 0	$ 0	0	0
Distributions to Noncontrolling Interest			$ (3)	$ (1)

EASTMAN CHEMICAL CO 10-Q