REVENUE (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Revenue from External Customer [Line Items]
Revenue, Percentage from Products and Service Transferred to Customers	98.00%	99.00%
Revenue, Remaining Performance Obligation, Amount	$ 942		$ 977
Revenues	11,882	$ 9,770
Contract with Customer, Liability, Revenue Recognized	40	35
Contract with Customer, Asset, Reclassified to Receivable		10
Accounts and notes receivable - Trade	5,576		4,839
Contract assets - current 1	82		58
Contract assets - noncurrent 2	33		11
Contract liabilities - current 3	307		349
Contract liabilities - noncurrent 4	1,951		1,915
The Dow Chemical Company [Domain]
Revenue from External Customer [Line Items]
Accounts and notes receivable - Trade	5,576		$ 4,839
U.S. & Canada
Revenue from External Customer [Line Items]
Revenues	4,028	3,550
EMEAI 1
Revenue from External Customer [Line Items]
Revenues	4,329	3,411
Asia Pacific
Revenue from External Customer [Line Items]
Revenues	2,365	1,845
Latin America
Revenue from External Customer [Line Items]
Revenues	$ 1,160	964
Maximum [Member] | P20Y: 2020-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	20 years
Packaging & Specialty Plastics [Member]
Revenue from External Customer [Line Items]
Revenues	$ 6,082	4,609
Packaging & Specialty Plastics [Member] | Hydrocarbons & Energy [Member]
Revenue from External Customer [Line Items]
Revenues	1,751	1,219
Packaging & Specialty Plastics [Member] | Packaging and Specialty Plastics [Member]
Revenue from External Customer [Line Items]
Revenues	4,331	3,390
Industrial Intermediates & Infrastructure [Member]
Revenue from External Customer [Line Items]
Revenues	3,607	3,045
Industrial Intermediates & Infrastructure [Member] | Industrial Solutions [Member]
Revenue from External Customer [Line Items]
Revenues	1,049	1,054
Industrial Intermediates & Infrastructure [Member] | Polyurethanes & CAV [Member]
Revenue from External Customer [Line Items]
Revenues	2,556	1,988
Industrial Intermediates & Infrastructure [Member] | Other [Member]
Revenue from External Customer [Line Items]
Revenues	2	3
Performance Materials & Coatings [Member]
Revenue from External Customer [Line Items]
Revenues	2,123	2,065
Performance Materials & Coatings [Member] | Coatings and Performance Monomers [Member]
Revenue from External Customer [Line Items]
Revenues	855	828
Performance Materials & Coatings [Member] | Consumer Solutions [Member]
Revenue from External Customer [Line Items]
Revenues	1,268	1,237
Corporate Segment [Member]
Revenue from External Customer [Line Items]
Revenues	$ 70	$ 51