Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accum. Other Comp Loss
Beginning balance at Dec. 31, 2016		$ 0	$ 138	$ 2,980	$ (1,320)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Capital contribution from The Dow Chemical Company			0
Net Income Attributable to Union Carbide Corporation	$ 205			205
Dividends declared				603
Stockholders' Equity, Other				0
Other Comprehensive Income (Loss), Net of Tax	(32)				(32)
Ending balance at Dec. 31, 2017	1,368	0	138	2,582	(1,352)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of accounting standard (Note 1)				0	0
Capital contribution from The Dow Chemical Company			0
Net Income Attributable to Union Carbide Corporation	1,055			1,055
Dividends declared				553
Stockholders' Equity, Other				0
Other Comprehensive Income (Loss), Net of Tax	45				45
Ending balance at Dec. 31, 2018	1,915	0	138	3,338	(1,561)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of accounting standard (Note 1)				254	(254)
Capital contribution from The Dow Chemical Company			3
Net Income Attributable to Union Carbide Corporation	627			627
Dividends declared				1,042
Stockholders' Equity, Other				(1)
Other Comprehensive Income (Loss), Net of Tax	(104)				(104)
Ending balance at Dec. 31, 2019	$ 1,398	$ 0	$ 141	2,922	(1,665)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of accounting standard (Note 1)				$ 0	$ 0