CONSOLIDATED FINANCIAL STATEMENTS Changes to Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories	$ 9,577	$ 8,365	$ 8,376
Other current assets	658	687	627
Total current assets	28,514	27,293	27,244
Deferred income tax assets	1,784	1,757	1,722
Deferred charges and other assets	946	872	829
Total other assets	22,250	22,116	22,038
Total assets	81,371	80,067	79,940
Accounts payable - Other	3,682	3,072	3,062
Income taxes payable	756	692	694
Accrued and other current liabilities	3,348	4,075	4,025
Total current liabilities	15,094	14,435	14,377
Other noncurrent obligations	6,121	6,111	5,994
Total other noncurrent liabilities	18,710	18,906	18,789
Retained earnings	28,261	27,982	28,050
Accumulated other comprehensive loss	(8,088)	(8,571)	(8,591)
The Dow Chemical Company's stockholders' equity	26,781	25,775	25,823
Total equity	27,971	26,961	27,009	$ 28,334	$ 27,229
Total Liabilities and Equity	81,371	80,067	$ 79,940
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories	30	(11)
Other current assets	(43)	29
Total current assets	(13)	18
Deferred income tax assets	(27)	25
Deferred charges and other assets	(43)	43
Total other assets	(70)	68
Total assets	(83)	86
Accounts payable - Other	(10)	10
Income taxes payable	2	(2)
Accrued and other current liabilities	(34)	50
Total current liabilities	(42)	58
Other noncurrent obligations	(120)	117
Total other noncurrent liabilities	(120)	117
Retained earnings	79	(89)
Accumulated other comprehensive loss		0
The Dow Chemical Company's stockholders' equity	79	(89)
Total equity	79	(89)
Total Liabilities and Equity	$ (83)	86
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories		0
Other current assets		0
Total current assets		0
Deferred income tax assets		0
Deferred charges and other assets		0
Total other assets		0
Total assets		0
Accounts payable - Other		0
Income taxes payable		0
Accrued and other current liabilities		0
Total current liabilities		0
Other noncurrent obligations		0
Total other noncurrent liabilities		0
Retained earnings		(20)
Accumulated other comprehensive loss		20
The Dow Chemical Company's stockholders' equity		0
Total equity		0
Total Liabilities and Equity		0
Accounting Standards Update 2016-16 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Inventories		0
Other current assets		31
Total current assets		31
Deferred income tax assets		10
Deferred charges and other assets		0
Total other assets		10
Total assets		41
Accounts payable - Other		0
Income taxes payable		0
Accrued and other current liabilities		0
Total current liabilities		0
Other noncurrent obligations		0
Total other noncurrent liabilities		0
Retained earnings		41
Accumulated other comprehensive loss		0
The Dow Chemical Company's stockholders' equity		41
Total equity		41
Total Liabilities and Equity		$ 41