Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income attributable to Union Carbide Corporation	$ 59	$ 122	$ 273	$ 477
Cumulative translation adjustments	0	1	3	1
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	20	14	59	43
Other Comprehensive Income (Loss), Net of Tax	20	15	62	44
Comprehensive income attributable to Union Carbide Corporation	$ 79	$ 137	$ 335	$ 521