COMMITMENTS AND CONTINGENT LIABILITIES (Asbestos-Related Matters of Union Carbide Corporation) (Table and Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Loss Contingencies [Line Items]
Liability for Asbestos Claims and Defense Costs Gross	$ 1,080	$ 1,098
Percentage of recorded asbestos liability related to pending claims	24.00%
Percentage of recorded asbestos liability related to future claims	76.00%

Carrying amount as of the balance sheet date of reserves for the costs of settling insured claims and costs incurred in the claims settlement process, and reserves for defense and processing costs attributable to asbestos claims

No definition available.

Name:	ucc_LiabilityforAsbestosClaimsandDefenseCostsGross
Namespace Prefix:	ucc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant