COMMITMENTS AND CONTINGENCIES (Environmental Matters) (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Site Contingency [Line Items]
Accrual for Environmental Loss Contingencies, Revision in Estimates				$ 399
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrual adjustment					$ 159	$ 285	$ 399
Payments against reserve					(162)	(198)
Foreign currency impact					(21)	2
Environmental Remediation Expense					(158)	(234)	(588)
Capital expenditures for environmental protection					65	80	83
Restructuring, goodwill impairment and asset related charges - net					6	708	3,219
2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	$ 573		$ 575
Costs Associated with Exit and Disposal Activities [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	80		81
Environmental Remediation [Member] | Costs Associated with Exit and Disposal Activities [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	56
Packaging & Specialty Plastics [Member]
Site Contingency [Line Items]
Accrual for Environmental Loss Contingencies, Revision in Estimates				5
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrual adjustment							5
Restructuring, goodwill impairment and asset related charges - net					8	30	439
Packaging & Specialty Plastics [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	11
Packaging & Specialty Plastics [Member] | Costs Associated with Exit and Disposal Activities [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	0
Industrial Intermediates & Infrastructure [Member]
Site Contingency [Line Items]
Accrual for Environmental Loss Contingencies, Revision in Estimates				8
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrual adjustment							8
Restructuring, goodwill impairment and asset related charges - net					1	22	1,175
Industrial Intermediates & Infrastructure [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	22
Industrial Intermediates & Infrastructure [Member] | Costs Associated with Exit and Disposal Activities [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	0
Performance Materials & Coatings [Member]
Site Contingency [Line Items]
Accrual for Environmental Loss Contingencies, Revision in Estimates				50
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrual adjustment							50
Restructuring, goodwill impairment and asset related charges - net					10	192	1,076
Performance Materials & Coatings [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	177
Performance Materials & Coatings [Member] | Costs Associated with Exit and Disposal Activities [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	61
Performance Materials & Coatings [Member] | Environmental Remediation [Member] | Costs Associated with Exit and Disposal Activities [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	52
Corporate Segment [Member]
Site Contingency [Line Items]
Accrual for Environmental Loss Contingencies, Revision in Estimates				336
Accrual for Environmental Loss Contingencies [Roll Forward]
Accrual adjustment							336
Restructuring, goodwill impairment and asset related charges - net					(13)	464	529
Corporate Segment [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	363
Corporate Segment [Member] | Costs Associated with Exit and Disposal Activities [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	19
Corporate Segment [Member] | Environmental Remediation [Member] | Costs Associated with Exit and Disposal Activities [Member] | 2020 Restructuring Program [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Restructuring, goodwill impairment and asset related charges - net	4
Tittabawassee and Saginaw Rivers, Saginaw Bay [Member]
Site Contingency [Line Items]
Accrued obligations for environmental matters	77	$ 77				77
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at Jan 1					77
Balance at Dec 31	77	77				77
Payments for Legal Settlements		15
Tittabawassee and Saginaw Rivers, Saginaw Bay - Local Projects [Member]
Accrual for Environmental Loss Contingencies [Roll Forward]
Payments for Legal Settlements		7
Other Environmental Matters
Site Contingency [Line Items]
Accrued obligations for environmental matters	1,244	1,244			1,220	1,244	1,155
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at Jan 1					1,244	1,155
Balance at Dec 31	1,244	1,244			1,220	1,244	$ 1,155
Other Environmental Matters | Superfund Sites
Site Contingency [Line Items]
Accrued obligations for environmental matters	248	248			237	248
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at Jan 1					248
Balance at Dec 31	248	248			237	248
Other Environmental Matters, Off-Site Matters
Site Contingency [Line Items]
Accrued obligations for environmental matters	107	107			104	107
Accrual for Environmental Loss Contingencies [Roll Forward]
Balance at Jan 1					107
Balance at Dec 31	107	107			104	107
Dow Silicones Corporation
Site Contingency [Line Items]
Indemnification asset	$ 115	$ 115			$ 95	$ 115
Dow Silicones Corporation | Environmental Issue [Member]
Site Contingency [Line Items]
Indemnification asset			$ 50	$ 48