Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net Income Attributable to Union Carbide Corporation	$ 1,055	$ 205	$ 89
Other Comprehensive Income (Loss), Net of Tax
Cumulative translation adjustments	2	3	(1)
Pension and other postretirement benefit plans	43	(35)	(91)
Net other comprehensive income	45	(32)	(92)
Comprehensive Income (Loss) Attributable to Union Carbide Corporation	$ 1,100	$ 173	$ (3)