COMMITMENTS AND CONTINGENT LIABILITIES Indemnifications with Corning (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 01, 2016
Other noncurrent assets
Loss Contingencies [Line Items]
Indemnification Asset	$ 33	$ 52
Other Current Assets [Member]
Loss Contingencies [Line Items]
Indemnification Asset	58	58
Dow Silicones Corporation [Member]
Loss Contingencies [Line Items]
Business Combination, Indemnification Assets, Percentage of Future Losses				50.00%
Indemnification Asset	115	100
Dow Silicones Corporation [Member] | Commercial Creditors Litigation [Member]
Loss Contingencies [Line Items]
Indemnification Asset			$ 37
Dow Silicones Corporation [Member] | Other Current Assets [Member] | Commercial Creditors Litigation [Member]
Loss Contingencies [Line Items]
Indemnification Asset	0	37
Environmental Issue [Member] | Dow Silicones Corporation [Member]
Loss Contingencies [Line Items]
Indemnification Asset	50		$ 48
Environmental Issue [Member] | Dow Silicones Corporation [Member] | Other noncurrent assets
Loss Contingencies [Line Items]
Indemnification Asset	$ 115	$ 63