INVESTMENTS IN RELATED COMPANIES - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Feb. 15, 2019
Schedule of Investments [Line Items]
Investments in related companies	$ 237	$ 238
Dow International Holdings Company [Member]
Schedule of Investments [Line Items]
Ownership Interest Percentage, Related Company	5.00%	5.00%	4.70%	11.90%
Cost Method Investments	$ 232	$ 232
Dow Quimica Mexicana S.A. de C.V. [Member]
Schedule of Investments [Line Items]
Ownership Interest Percentage, Related Company	15.00%	15.00%
Cost Method Investments	$ 5	$ 5
Other [Member]
Schedule of Investments [Line Items]
Ownership Interest Percentage, Related Company	0.00%	0.00%
Cost Method Investments	$ 0	$ 1