STOCK-BASED COMPENSATION STOCK-BASED COMPENSATION (Performance Deferred Stock) (Details) shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) shares	Mar. 31, 2017 shares	Sep. 30, 2017 USD ($) employees shares
Performance Deferred Compensation [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested at Jan 1, 2017		4,454	4,454
Granted		1,700	1,728
Canceled			(131)
Impact of Actual Performance on shares granted through Conversion Date			2,120
Converted to deferred stock			(8,171)
Nonvested at Sept 30, 2017	0		0
Deferred Compensation, Share-based Payments [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested at Jan 1, 2017		6,382	6,382
Granted		1,600	1,702
Canceled			(124)
Nonvested at Sept 30, 2017	13,951		13,951
The Dow Chemical Company 2012 Stock Incentive Plan [Member] | Deferred Compensation, Share-based Payments [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental Compensation Cost - Preferred Conversion Total | $			$ 25
Allocated Share-based Compensation Expense in 3Q17 | $	$ 15
Incremental Allocation Of Recognized Period Costs, Capitalized Amount - Preferred Conversion | $			$ 10
Number of Employees Affected - Preferred Conversion | employees			5,000