SEPARATION FROM DOWDUPONT Separation and Distribution, Tax Matters and Other Agreements (Details) - USD ($) $ in Millions	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Charges related to separation, distribution and tax matters agreements										$ 144
Deferred cash contribution	$ 400								$ 400	400
Cash payment related to divestiture									215
Cash receipt related to divestiture									98
Integration and separation costs 2	99	$ 164	$ 348	$ 452	$ 380	$ 313	$ 262	$ 224		1,063	$ 1,179	$ 798
Integration and separation costs [Member]
Charges related to separation, distribution and tax matters agreements									24
Sundry Income (Expense), Net
Charges related to separation, distribution and tax matters agreements									69	69	0	0
Other current assets
Indemnification asset	58								58	58
Other Noncurrent Assets [Member]
Indemnification asset	52								52	52
Accrued and Other Current Liabilities [Member]
Indemnification liability	352								352	352
Deferred cash contribution	130								130	130
Other Noncurrent Obligations
Indemnification liability	96								96	96
Deferred cash contribution	270								$ 270	270
The Dow Chemical Company
Integration and separation costs 2	$ 99	$ 164	$ 324	$ 452						1,039	1,179	798
The Dow Chemical Company | Sundry Income (Expense), Net
Charges related to separation, distribution and tax matters agreements										$ (6)	$ 0	$ 0