Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]
Union Carbide Corporation's Stockholder's Equity at Dec. 31, 2017		$ 0	$ 138	$ 2,582	$ (1,352)
Net income attributable to Union Carbide Corporation	$ 743			743
Dividends, Common Stock				(423)
Stockholders' Equity, Other				0
Other Comprehensive Income (Loss), Net of Tax	51				51
Union Carbide Corporation's Stockholder's Equity at Sep. 30, 2018	1,739	0	138	3,156	(1,555)
Union Carbide Corporation's Stockholder's Equity at Jun. 30, 2018				3,061	(1,572)
Net income attributable to Union Carbide Corporation	272			272
Dividends, Common Stock				(177)
Stockholders' Equity, Other				0
Other Comprehensive Income (Loss), Net of Tax	17				17
Union Carbide Corporation's Stockholder's Equity at Sep. 30, 2018	1,739	0	138	3,156	(1,555)
Union Carbide Corporation's Stockholder's Equity at Dec. 31, 2018	1,915	0	138	3,338	(1,561)
Net income attributable to Union Carbide Corporation	477			477
Dividends, Common Stock				(922)
Stockholders' Equity, Other				(1)
Other Comprehensive Income (Loss), Net of Tax	44				44
Union Carbide Corporation's Stockholder's Equity at Sep. 30, 2019	1,513	0	138	2,892	(1,517)
Union Carbide Corporation's Stockholder's Equity at Jun. 30, 2019				2,882	(1,532)
Net income attributable to Union Carbide Corporation	122			122
Dividends, Common Stock				(112)
Stockholders' Equity, Other				0
Other Comprehensive Income (Loss), Net of Tax	15				15
Union Carbide Corporation's Stockholder's Equity at Sep. 30, 2019	$ 1,513	$ 0	$ 138	$ 2,892	$ (1,517)