SUPPLEMENTARY INFORMATION (Sundry Income, Net) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplementary Information [Line Items]
Net gain (loss) on sales of property	$ (1)	$ 0	$ 23
Non-operating pension and other postretirement benefit plan net credits (costs)	(17)	(1)	8
Net gain on sale of a nonconsolidated affiliate	0	0	4
Other - net	(12)	(9)	(3)
Total sundry income (expense) - net	(82)	(62)	(23)
Administrative and overhead fees [Member] | The Dow Chemical Company [Member]
Supplementary Information [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	(24)	(30)	(33)
Net Commission Expense [Member]
Supplementary Information [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	(23)	(22)	(22)
Acetone Derivatives [Member]
Supplementary Information [Line Items]
Net gain (loss) on sales of property	$ (5)	$ 0	$ 0