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Entity Address, City or Town Entity Address, City or Town Dividends Declared Dividends Declared [Table Text Block] Asia Pacific Asia Pacific [Member] Current Fiscal Year End Date Current Fiscal Year End Date The Dow Chemical Company [Member] The Dow Chemical Company [Member] The Dow Chemical Company [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Investment Income, Dividend Investment Income, Dividend Document Information [Line Items] Document Information [Line Items] Accounts Receivable from Related Companies Accounts Receivable from Related Companies Accounts Receivable from Related Companies Related Party Transaction [Domain] Related Party Transaction [Domain] Commodity And Raw Material Purchases Commodity And Raw Material Purchases [Member] Commodity And Raw Material Purchases Intangible Asset, Finite-Lived, Accumulated Amortization Intangible Asset, Finite-Lived, Accumulated Amortization Entity File Number Entity File Number Total other comprehensive income Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax UNITED STATES UNITED STATES Common stock, shares issued Common Stock, Shares, Issued Finished goods Inventory, Finished Goods, Gross ACCUMULATED OTHER COMPREHENSIVE LOSS Comprehensive Income (Loss) Note [Text Block] Equity Components [Axis] Equity Components [Axis] Related Party Transactions, by Related Party [Axis] Related and Nonrelated Parties [Axis] Restructuring Reserve, Current Restructuring Reserve, Current Entity Interactive Data Current Entity Interactive Data Current Long-term Debt Long-Term Debt Long-term Debt [Member] Long-Term Debt [Member] Supplies Other Inventory, Supplies, Gross Ownership Interest Percentage, Related Company Ownership Interest Percentage, Related Company Ownership Interest Percentage, Related Company Supplier Finance Program [Line Items] Supplier Finance Program [Line Items] Supplier Finance Program [Domain] Supplier Finance Program [Domain] Entity Small Business Entity Small Business Comprehensive income attributable to Union Carbide Corporation Comprehensive Income (Loss), Net of Tax, Attributable to Parent Document Period End Date Document Period End Date Cash used for investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Accounts payable Increase (Decrease) in Accounts Payable, Trade Pension and other postretirement benefit plans Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Proceeds from Sales of Business, Affiliate and Productive Assets Proceeds from Sales of Business, Affiliate and Productive Assets Deferred charges and other assets Other Assets, Noncurrent Document Type Document Type Activity Based Costs Activity Based Costs [Member] Activity Based Costs Financial Instruments Gross Unrealized Gains Financial Instruments Gross Unrealized Gains This item represents the gross unrealized gains of debt and equity securities, derivatives, and long-term debt. 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Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Asset Class [Domain] Asset Class [Domain] Related Party Transactions [Abstract] Related Party Transactions [Abstract] Geographical [Axis] Geographical [Axis] Other Receivables, Net, Current Other Receivables, Net, Current Contract with Customer, Liability Contract with Customer, Liability Entity Emerging Growth Company Entity Emerging Growth Company Related Party Transaction [Line Items] Related Party Transaction [Line Items] Change in noncurrent receivable from related company Increase (Decrease) in Due from Related Parties Entity Tax Identification Number Entity Tax Identification Number Notes payable to related companies Notes payable to related companies Notes payable to related companies Percentage of recorded asbestos liability related to pending claims Asbestos Related Liability Pending Claims Percentage The percentage of the recorded asbestos liability related to pending claims. 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Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Income Statement Location [Axis] Location, Statement of Income, Balance [Axis] Total Liabilities and Equity Liabilities and Equity Variable Lease, Cost Variable Lease, Cost Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Equity, Including Portion Attributable to Noncontrolling Interest Interest Income, Other Interest Income, Other Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Table] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Table] Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Asset Class [Axis] Asset Class [Axis] Dividends, Common Stock Dividends, Common Stock Net periodic benefit cost (credit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Related Party [Domain] Related and Nonrelated Parties [Domain] Restructuring and asset related charges - net Restructuring Charges Inventory Disclosure [Abstract] Inventory Disclosure [Abstract] Common stock, shares authorized Common Stock, Shares Authorized Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Accounts Payable to Related Company Accounts Payable to Related Company Accounts Payable to Related Company Schedule of Restructuring and Related Costs [Table] Restructuring Cost [Table] Income taxes receivable Income Taxes Receivable, Current Sundry income (expense) - net Other Operating Income (Expense), Net Related Party Transaction [Axis] Related Party Transaction [Axis] Document Quarterly Report Document Quarterly Report Rest of World Rest of World [Member] Rest of World (excluding United States and Asia Pacific) [Member] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Long-Lived Asset Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Long-Lived Asset [Table Text Block] Repayments of Long-term Debt Repayments of Long-Term Debt Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Restructuring Reserve Restructuring Reserve Equity Component [Domain] Equity Component [Domain] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Capital expenditures Capital expenditures Payments to Acquire Productive Assets Trade Accounts Payable, Trade, Current Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue [Abstract] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue [Abstract] Site Contingency [Table] Site Contingency [Table] Restructuring and Related Activities Disclosure Restructuring and Related Activities Disclosure [Text Block] Long-Term Debt Long-Term Debt and Lease Obligation Inventory Adjustments Inventory Adjustments Restructuring Type [Axis] Restructuring Type [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Other Noncash Income (Expense) Other Noncash Income (Expense) Retirement Plan Type [Domain] Retirement Plan Type [Domain] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current Provision (credit) for deferred income tax Deferred Income Tax Expense (Benefit) Selling, general and administrative expenses Selling, General and Administrative Expense Cash and Cash Equivalent Cash and cash equivalents at end of period Cash and Cash Equivalent Type of Restructuring [Domain] Type of Restructuring [Domain] Pension and other postretirement benefits - noncurrent Postemployment Benefits Liability, Noncurrent Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items] COMMITMENTS AND CONTINGENCIES DISCLOSURE Commitments and Contingencies Disclosure [Text Block] Cash Equivalents, Fair Value Cash Equivalents, Fair Value Cash Equivalents, Fair Value Depreciation and amortization Depreciation, Depletion and Amortization Entity Central Index Key Entity Central Index Key Inventory, Gross Inventory, Gross Common stock (authorized: 1,000 shares of $0.01 par value each; issued: 935.51 shares) Common Stock, Value, Outstanding Net Commission Expense Net Commission Expense [Member] Net Commission Expense [Member] Less accumulated depreciation Property, Plant, and Equipment, Accumulated Depreciation, Depletion, and Amortization Additional paid-in capital Additional Paid in Capital, Common Stock Equity [Abstract] Cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Statement [Line Items] Income Statement [Abstract] Document Transition Report Document Transition Report Entity Address, Address Line One Entity Address, Address Line One Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Super Fund Sites [Member] Super Fund Sites [Member] Super Fund Sites [Member] Provision for income taxes Income Tax Expense (Benefit) Restructuring Plan [Domain] Restructuring Plan [Domain] Dow International Holdings Company [Member] Dow International Holdings Company [Member] Dow International Holdings Company [Member] Deferred Tax Assets, Deferred Income Deferred Tax Assets, Deferred Income Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Research and development expenses Research and Development Expense (Excluding Acquired in Process Cost) Total investments Long-Term Investments and Receivables, Net City Area Code City Area Code Defined Benefit Plan, Amortization of Gain (Loss) Defined Benefit Plan, Amortization of Gain (Loss) Accounting Standards Update and Change in Accounting Principle Accounting Standards Update and Change in Accounting Principle [Text Block] Net Income Attributable to Union Carbide Corporation Net income (loss) attributable to Union Carbide Corporation Net Income (Loss) Attributable to Parent Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Net sales to related companies Net sales to related companies Net sales to related companies Document Information [Table] Document Information [Table] Costs and Expenses, Related Party Costs and Expenses, Related Party Balance Sheet Location [Axis] Location, Statement of Financial Position, Balance [Axis] Statement [Table] Statement [Table] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue [Table Text Block] Dividends paid to parent Payments of Dividends Payments of Dividends Schedule of Other Segment Information Schedule of Other Segment Information [Table Text Block] Schedule of Other Segment Information Liabilities, Other than Long-term Debt, Noncurrent Liabilities, Other than Long-Term Debt, Noncurrent Statement [Line Items] Statement [Line Items] Other investments Marketable Securities, Noncurrent Total Assets Assets Defined Benefit Plan [Table] Defined Benefit Plan [Table] Accrual for Environmental Loss Contingencies Accrual for Environmental Loss Contingencies