Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) [Member]
Union Carbide Corporation' stockholder's equity, beginning balance at Dec. 31, 2016	$ 1,798	$ 0	$ 138	$ 2,980	$ (1,320)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Union Carbide Corporation	355	0	0	355	0
Other comprehensive income	27	0	0	0	27
Dividends declared	(350)	0	0	(350)	0
Other	1	0	0	1	0
Union Carbide Corporation's stockholder's equity, ending balance at Jun. 30, 2017	1,831	0	138	2,986	(1,293)
Union Carbide Corporation' stockholder's equity, beginning balance at Dec. 31, 2017	1,368	0	138	2,582	(1,352)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to Union Carbide Corporation	471	0	0	471	0
Other comprehensive income	34	0	0	0	34
Dividends declared	(246)	0	0	(246)	0
Union Carbide Corporation's stockholder's equity, ending balance at Jun. 30, 2018	1,627	0	138	3,061	(1,572)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of accounting standard (Note 1)	$ 0	$ 0	$ 0	$ 254	$ (254)