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	399	0	0	399	0
Other comprehensive income	40	0	0	0	40
Dividends declared	(531)	0	0	(531)	0
Union Carbide Corporation's stockholder's equity, ending balance at Sep. 30, 2017	1,706	0	138	2,848	(1,280)
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	743	0	0	743	0
Other comprehensive income	51	0	0	0	51
Dividends declared	(423)	0	0	(423)	0
Union Carbide Corporation's stockholder's equity, ending balance at Sep. 30, 2018	1,739	0	138	3,156	(1,555)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of accounting standard (Note 1)	$ 0	$ 0	$ 0	$ 254	$ (254)