SELECTED QUARTERLY FINANCIAL DATA Quarterly Financial Information Disclosure (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 10,204	$ 10,764	$ 11,014	$ 10,969	$ 11,944	$ 12,634	$ 12,789	$ 12,237	$ 42,951	$ 49,604	$ 43,730
Cost of sales	8,718	9,377	9,420	9,142	10,098	10,456	10,540	9,980	36,657	41,074	36,350
Gross margin	1,486	1,387	1,594	1,827	1,846	2,178	2,249	2,257	6,294	8,530
Restructuring, goodwill impairment and asset related charges - net	2,851	147	65	156	46	48	40	87	3,219	221	2,739
Integration and separation costs 2	99	164	348	452	380	313	262	224	1,063	1,179	798
Income (loss) from continuing operations, net of tax	(2,310)	347	90	156	491	714	810	925	(1,717)	2,940	(1,287)
Income from discontinued operations, net of tax	0	0	0	445	432	335	554	514	445	1,835	1,882
Net income (loss)	(2,310)	347	90	601	923	1,049	1,364	1,439	(1,272)	4,775	595
Net income (loss) available for The Dow Chemical Company common stockholder	$ (2,323)	$ 333	$ 75	$ 556	$ 891	$ 1,013	$ 1,333	$ 1,404	$ (1,359)	$ 4,641	$ 465
Earnings (loss) per common share from continuing operations - basic	$ (3.14)	$ 0.45	$ 0.10	$ 0.16	$ 0.63	$ 0.91	$ 1.05	$ 1.21	$ (2.42)	$ 3.80	$ (1.88)
Earnings (loss) per common share from continuing operations - diluted	(3.14)	0.45	0.10	$ 0.16	$ 0.63	$ 0.91	$ 1.05	$ 1.21	(2.42)	3.80	(1.88)
Dividends declared per share of common stock	0.70	0.70	0.70						2.10	$ 0	$ 1.38
Maximum
Condensed Financial Statements, Captions [Line Items]
Share Price	55.99	52.79	59.71						55.99
Minimum
Condensed Financial Statements, Captions [Line Items]
Share Price	$ 43.85	$ 40.71	$ 46.76						$ 43.85
The Dow Chemical Company
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 10,204	$ 10,764	$ 11,014	$ 10,969					$ 42,951	$ 49,604	$ 43,730
Cost of sales	8,719	9,377	9,419	9,142					36,657	41,074	36,350
Gross margin	1,485	1,387	1,595	1,827					6,294
Restructuring, goodwill impairment and asset related charges - net	2,851	147	65	156					3,219	221	2,739
Integration and separation costs 2	99	164	324	452					1,039	1,179	798
Income (loss) from continuing operations, net of tax	(2,292)	324	217	156					(1,595)	2,940	(1,287)
Income from discontinued operations, net of tax	0	0	0	445					445	1,835	1,882
Net income (loss)	(2,292)	324	217	601					(1,150)	4,775	595
Net income (loss) available for The Dow Chemical Company common stockholder	$ (2,305)	$ 310	$ 202	$ 556					$ (1,237)	$ 4,641	$ 465
Dividends declared per share of common stock											$ 1.38