Unaudited Interim Consolidated Statement Equity - 9 months ended Sep. 30, 2017 - 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, 2016		140,660,447	26,950,910
Balance as of the beginning of the period at Dec. 31, 2016	$ 3,021
Total Celanese Corporation stockholders' equity at Dec. 31, 2016	$ 2,588	$ 0	$ (1,531)	$ 157	$ 4,320	$ (358)
Stock option exercises, shares		20,151
Stock option exercises, net of tax		$ 0		1
Purchases of treasury stock, shares		(5,436,803)
Purchases of treasury stock, including related fees		$ 0
Stock awards, shares		392,587
Stock awards		$ 0
Purchases of treasury stock, shares	5,436,803		5,436,803
Purchases of treasury stock, including related fees	$ (500)		$ (500)
Stock-based compensation, net of tax				13
Cumulative effect adjustment from adoption of new accounting standard (Note 1)					(1)
Net earnings (loss) attributable to Celanese Corporation	640				640
Series A common stock dividends					(178)
Other comprehensive income (loss), net of tax	152					152
Balance as of the end of the period, shares at Sep. 30, 2017		135,636,382	32,387,713
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2016	433						$ 433
Net earnings (loss) attributable to noncontrolling interests	5						5
(Distributions to) contributions from noncontrolling interests							(18)
Stockholders' Equity Attributable to Noncontrolling Interest at Sep. 30, 2017	420						$ 420
Total Celanese Corporation stockholders' equity at Sep. 30, 2017	2,715	$ 0	$ (2,031)	$ 171	$ 4,781	$ (206)
Balance as of the end of the period at Sep. 30, 2017	$ 3,135