Unaudited Interim Consolidated Statement Equity - 3 months ended Mar. 31, 2018 - USD ($) $ in Millions	Total	Series A Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Balance as of the beginning of the period, shares at Dec. 31, 2017		135,769,256	32,387,713
Balance as of the beginning of the period at Dec. 31, 2017	$ 3,299
Total Celanese Corporation stockholders' equity at Dec. 31, 2017	$ 2,887	$ 0	$ (2,031)	$ 175	$ 4,920	$ (177)
Stock option exercises, shares		0
Stock option exercises, net of tax		$ 0
Purchases of treasury stock, shares		0
Purchases of treasury stock, including related fees		$ 0
Stock awards, shares		86,454
Stock awards		$ 0
Purchases of treasury stock, shares	0		0
Purchases of treasury stock, including related fees	$ 0		$ 0
Stock-based compensation, net of tax				17
Net earnings (loss) attributable to Celanese Corporation	363				363
Series A common stock dividends					(63)
Other comprehensive income (loss), net of tax	49					49
Balance as of the end of the period, shares at Mar. 31, 2018		135,855,710	32,387,713
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2017	412						$ 412
Net earnings (loss) attributable to noncontrolling interests	2						2
(Distributions to) contributions from noncontrolling interests							(2)
Stockholders' Equity Attributable to Noncontrolling Interest at Mar. 31, 2018	412						$ 412
Total Celanese Corporation stockholders' equity at Mar. 31, 2018	3,253	$ 0	$ (2,031)	$ 192	$ 5,220	$ (128)
Balance as of the end of the period at Mar. 31, 2018	$ 3,665