SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Changes and Prior Period Adjustments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018	Dec. 31, 2015
Summary of Changes to the Consolidated Statements of Income
Cost of sales	$ 11,820	$ 11,933	$ 12,400	$ 11,552	$ 11,994	$ 10,663	$ 10,761	$ 10,194	$ 47,705	$ 43,612	$ 37,668
Research and development expenses									1,536	1,648	1,593
Selling, general and administrative expenses									2,846	2,920	2,953
Sundry income (expense) - net									181	195	1,486
Operating Activities
Accounts and notes receivable									(1,532)	(11,927)	(8,833)
Other assets and liabilities, net									(1,090)	(102)	(723)
Cash provided by (used for) operating activities									3,894	(4,958)	(2,957)
Investing Activities
Acquisitions of property and businesses, net of cash acquired									(20)	47	(187)
Cash acquired in step acquisition of nonconsolidated affiliate									0	0	1,070
Proceeds from interests in trade accounts receivable conduits									657	9,462	8,551
Other financing activities, net									(67)	(35)	(2)
Cash provided by (used for) investing activities									(2,128)	7,552	5,092
Financing Activities
Cash used for financing activities									(5,164)	(3,331)	(4,014)
Decrease in cash, cash equivalents and restricted cash									(3,498)	(417)	(1,956)
Cash, cash equivalents and restricted cash at beginning of year				6,207				6,624	6,207	6,624	8,580
Cash, cash equivalents and restricted cash at end of year	2,709				6,207				2,709	6,207	6,624
Summary of Impacts to the Consolidated Balance Sheet
Inventories	9,260				8,376				9,260	8,376		$ 8,365
Other current assets	852				627				852	627		687
Total current assets	25,263				27,244				25,263	27,244		27,293
Deferred income tax assets	2,031				1,722				2,031	1,722		1,757
Deferred charges and other assets	796				829				796	829		872
Total other assets	21,588				22,038				21,588	22,038		22,116
Total Assets	77,378				79,940				77,378	79,940		80,067
Accounts payable - Other	3,330				3,062				3,330	3,062		3,072
Income taxes payable	791				694				791	694		692
Accrued and other current liabilities	3,611				4,025				3,611	4,025		4,075
Total current liabilities	13,755				14,377				13,755	14,377		14,435
Other noncurrent obligations	5,368				5,994				5,368	5,994		6,111
Total other noncurrent liabilities	16,400				18,789				16,400	18,789		18,906
Retained earnings	29,808				28,050				29,808	28,050		27,982
Accumulated other comprehensive loss	(9,885)				(8,591)				(9,885)	(8,591)		(8,571)
The Dow Chemical Company's stockholders' equity	26,831				25,823				26,831	25,823		25,775
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	27,969				27,009				27,969	27,009	27,229	26,961	$ 26,183
Total Liabilities and Equity	77,378				79,940				77,378	79,940		80,067
Balance at Dec 31, 2018 Excluding Adoption of Topic 606
Summary of Impacts to the Consolidated Balance Sheet
Inventories	9,266								9,266
Other current assets	836								836
Total current assets	25,253								25,253
Deferred income tax assets	2,005								2,005
Deferred charges and other assets	753								753
Total other assets	21,519								21,519
Total Assets	77,299								77,299
Accounts payable - Other	3,320								3,320
Income taxes payable	793								793
Accrued and other current liabilities	3,596								3,596
Total current liabilities	13,732								13,732
Other noncurrent obligations	5,228								5,228
Total other noncurrent liabilities	16,260								16,260
Retained earnings	29,892								29,892
The Dow Chemical Company's stockholders' equity	26,915								26,915
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	28,053								28,053
Total Liabilities and Equity	77,299								77,299
ASU 2016-15 and ASU 2016-18
Operating Activities
Accounts and notes receivable										(11,927)	(8,833)
Proceeds from interests in trade accounts receivable conduits										0	0
Other assets and liabilities, net										(102)	(723)
Cash provided by (used for) operating activities										(4,958)	(2,957)
Investing Activities
Payment into escrow account										0	0
Distribution from escrow account										0	0
Acquisitions of property and businesses, net of cash acquired										47	(187)
Cash acquired in step acquisition of nonconsolidated affiliate										0	1,070
Proceeds from interests in trade accounts receivable conduits										9,462	8,551
Other financing activities, net										(35)	(2)
Cash provided by (used for) investing activities										7,552	5,092
Financing Activities
Cash used for financing activities										(3,331)	(4,014)
Decrease in cash, cash equivalents and restricted cash										(417)	(1,956)
Cash, cash equivalents and restricted cash at beginning of year				6,207				6,624	6,207	6,624	8,580
Cash, cash equivalents and restricted cash at end of year					6,207					6,207	6,624
Topic 606 | Adjustments
Summary of Impacts to the Consolidated Balance Sheet
Inventories	6								6
Other current assets	(16)								(16)
Total current assets	(10)								(10)
Deferred income tax assets	(26)								(26)
Deferred charges and other assets	(43)								(43)
Total other assets	(69)								(69)
Total Assets	(79)								(79)
Accounts payable - Other	(10)								(10)
Income taxes payable	2								2
Accrued and other current liabilities	(15)								(15)
Total current liabilities	(23)								(23)
Other noncurrent obligations	(140)								(140)
Total other noncurrent liabilities	(140)								(140)
Retained earnings	84								84
The Dow Chemical Company's stockholders' equity	84								84
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	84								84
Total Liabilities and Equity	$ (79)								(79)
ASU 2016-01
Summary of Impacts to the Consolidated Balance Sheet
Accumulated other comprehensive loss												20
As Filed
Summary of Changes to the Consolidated Statements of Income
Cost of sales										44,308	37,640
Research and development expenses										1,637	1,584
Selling, general and administrative expenses										2,917	2,956
Sundry income (expense) - net										877	1,452
Operating Activities
Accounts and notes receivable										(4,734)	(1,539)
Proceeds from interests in trade accounts receivable conduits										2,269	1,257
Other assets and liabilities, net										(104)	(717)
Cash provided by (used for) operating activities										4,502	5,600
Investing Activities
Payment into escrow account										(130)	(835)
Distribution from escrow account										130	835
Acquisitions of property and businesses, net of cash acquired										16	(187)
Cash acquired in step acquisition of nonconsolidated affiliate										0	1,050
Proceeds from interests in trade accounts receivable conduits										0	0
Other financing activities, net										(4)	(2)
Cash provided by (used for) investing activities										(1,941)	(3,479)
Financing Activities
Cash used for financing activities										(3,300)	(4,014)
Decrease in cash, cash equivalents and restricted cash										(419)	(1,970)
Cash, cash equivalents and restricted cash at beginning of year				$ 6,188				$ 6,607	$ 6,188	6,607	8,577
Cash, cash equivalents and restricted cash at end of year					6,188					6,188	$ 6,607
Summary of Impacts to the Consolidated Balance Sheet
Inventories					8,376					8,376
Other current assets					627					627
Total current assets					27,244					27,244
Deferred income tax assets					1,722					1,722
Deferred charges and other assets					829					829
Total other assets					22,038					22,038
Total Assets					79,940					79,940
Accounts payable - Other					3,062					3,062
Income taxes payable					694					694
Accrued and other current liabilities					4,025					4,025
Total current liabilities					14,377					14,377
Other noncurrent obligations					5,994					5,994
Total other noncurrent liabilities					18,789					18,789
Retained earnings					28,050					28,050
Accumulated other comprehensive loss					(8,591)					(8,591)
The Dow Chemical Company's stockholders' equity					25,823					25,823
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest					27,009					27,009
Total Liabilities and Equity					$ 79,940					$ 79,940
Adjustments due to: | Topic 606
Summary of Impacts to the Consolidated Balance Sheet
Inventories												(11)
Other current assets												29
Total current assets												18
Deferred income tax assets												25
Deferred charges and other assets												43
Total other assets												68
Total Assets												86
Accounts payable - Other												10
Income taxes payable												(2)
Accrued and other current liabilities												50
Total current liabilities												58
Other noncurrent obligations												117
Total other noncurrent liabilities												117
Retained earnings												(89)
Accumulated other comprehensive loss												0
The Dow Chemical Company's stockholders' equity												(89)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest												(89)
Total Liabilities and Equity												86
Adjustments due to: | ASU 2016-01
Summary of Impacts to the Consolidated Balance Sheet
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
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest												0
Total Liabilities and Equity												0
Adjustments due to: | ASU 2016-16
Summary of Impacts to the Consolidated Balance Sheet
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
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest												41
Total Liabilities and Equity												$ 41