SUPPLEMENTARY INFORMATION (Sundry Income, Net) (Details) - USD ($) $ in Millions			3 Months Ended		12 Months Ended
	Oct. 05, 2015	May 05, 2015	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplementary Information [Line Items]
Gain on sales of other assets and investments					$ 182	$ 170	$ 237
Interest income					106	107	71
Foreign exchange losses					(72)	(126)	(191)
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net					0	2,445	361
Disposal Group,Including Discontinued Operation, Nonrecurring Transaction Costs					0	41	119
Equity Method Investment, Realized Gain (Loss) on Disposal						0	0
Gain (Loss) on Extinguishment of Debt	$ (68)				0	0	(8)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, before Tax					8	0	(4)
Other Income					116	125	49
Sundry income (expense) - net					877	1,452	4,716
AgroFresh [Member]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal					0	(25)	618
MEGlobal [Member]
Supplementary Information [Line Items]
Equity Method Investment, Realized Gain (Loss) on Disposal					0	(1)	723
Sale of an Agricultural Sciences product line [Member]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal					0	0	44
ANGUS Chemical Company [Member]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal					0	0	682
Sodium Borohydride business [Member]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal					0	0	20
AgroFresh [Member]
Supplementary Information [Line Items]
Loss on mark to market						(5)	(8)
Tender Offer of Long Term Debt [Member]
Supplementary Information [Line Items]
Gain (Loss) on Extinguishment of Debt							(68)
Dow Corning Corporation [Member]
Supplementary Information [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain (Loss), Net					0	2,445	0
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain			$ 2,445
Univation Technologies, LLC [Member]
Supplementary Information [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain		$ 361			0	0	361
Breast Implant and Other Products Liability Claims [Domain] | Impact to Sundry income (expense) [Member]
Supplementary Information [Line Items]
Estimated Litigation Liability, Noncurrent				$ 0	0	27	0
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Dow AgroSciences' Corn Seed Business [Member]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal					635	0	0
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Global Ethylene Acrylic Acid (EAA) [Member]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal					227	0	0
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | AgroFresh [Member]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal							626
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | ANGUS Chemical Company [Member]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal							682
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Sodium Borohydride business [Member]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal							20
Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations [Member] | Chlorine Value Chain [Domain]
Supplementary Information [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal				$ 2,233	7	6	2,233
Disposal Group,Including Discontinued Operation, Nonrecurring Transaction Costs							119
Gain (Loss) on Extinguishment of Debt	$ (68)
Nova Patent Infringement [Member]
Supplementary Information [Line Items]
Gain (loss) related to litigation settlement					137	0	0
Bayer CropScience v. Dow AgroSciences [Member]
Supplementary Information [Line Items]
Gain (loss) related to litigation settlement					(469)	0	0
Urethane Matters Class Action Lawsuit And Opt-Out Cases [Member]
Supplementary Information [Line Items]
Gain (loss) related to litigation settlement					$ 0	$ (1,235)	$ 0