Unaudited Interim Consolidated Statement Equity - USD ($)	Total	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
Total Celanese Corporation stockholders' equity at Dec. 31, 2017		$ 0	$ (2,031,000,000)	$ 175,000,000	$ 4,920,000,000	$ (177,000,000)
Stock option exercises, shares		0
Stock option exercises		$ 0		0
Purchases of treasury stock, shares		(888,383)
Purchases of treasury stock		$ 0
Stock awards, shares		137,275
Stock awards		$ 0
Purchases of treasury stock, shares	888,383		888,383
Purchases of treasury stock, including related fees	$ (100,000,000)		$ 100,000,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			0
Stock-based compensation, net of tax			$ 0	33,000,000
Net earnings (loss) attributable to Celanese Corporation	707,000,000				707,000,000
Common stock dividends					136,000,000
Other comprehensive income (loss), net of tax	(11,000,000)					(11,000,000)
Balance as of the end of the period, shares at Jun. 30, 2018		135,018,148	33,276,096
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2017							$ 412,000,000
Net earnings (loss) attributable to noncontrolling interests	3,000,000						3,000,000
(Distributions to) contributions from noncontrolling interests							8,000,000
Stockholders' Equity Attributable to Noncontrolling Interest at Jun. 30, 2018							407,000,000
Total Celanese Corporation stockholders' equity at Jun. 30, 2018	3,380,000,000	$ 0	$ (2,131,000,000)	208,000,000	5,491,000,000	(188,000,000)
Balance as of the end of the period at Jun. 30, 2018	3,787,000,000
Balance as of the beginning of the period, shares at Mar. 31, 2018		135,855,710	32,387,713
Total Celanese Corporation stockholders' equity at Mar. 31, 2018		$ 0	$ (2,031,000,000)	192,000,000	5,220,000,000	(128,000,000)
Stock option exercises, shares		0
Stock option exercises		$ 0		0
Purchases of treasury stock, shares		(888,383)
Purchases of treasury stock		$ 0
Stock awards, shares		50,821
Stock awards		$ 0
Purchases of treasury stock, shares			888,383
Purchases of treasury stock, including related fees			$ 100,000,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			0
Stock-based compensation, net of tax			$ 0	16,000,000
Net earnings (loss) attributable to Celanese Corporation	344,000,000				344,000,000
Common stock dividends					73,000,000
Other comprehensive income (loss), net of tax	(60,000,000)					(60,000,000)
Balance as of the end of the period, shares at Jun. 30, 2018		135,018,148	33,276,096
Stockholders' Equity Attributable to Noncontrolling Interest at Mar. 31, 2018							412,000,000
Net earnings (loss) attributable to noncontrolling interests	1,000,000						1,000,000
(Distributions to) contributions from noncontrolling interests							6,000,000
Stockholders' Equity Attributable to Noncontrolling Interest at Jun. 30, 2018							407,000,000
Total Celanese Corporation stockholders' equity at Jun. 30, 2018	3,380,000,000	$ 0	$ (2,131,000,000)	208,000,000	5,491,000,000	(188,000,000)
Balance as of the end of the period at Jun. 30, 2018	3,787,000,000
Balance as of the beginning of the period, shares at Dec. 31, 2018		128,095,849	40,323,105
Balance as of the beginning of the period at Dec. 31, 2018	3,379,000,000
Total Celanese Corporation stockholders' equity at Dec. 31, 2018	$ 2,984,000,000	$ 0	$ (2,849,000,000)	233,000,000	5,847,000,000	(247,000,000)
Stock option exercises, shares		14,045
Stock option exercises		$ 0		(1,000,000)
Purchases of treasury stock, shares		(4,890,155)
Purchases of treasury stock		$ 0
Stock awards, shares		520,610
Stock awards		$ 0
Purchases of treasury stock, shares	4,890,155		4,890,155
Purchases of treasury stock, including related fees	$ (500,000,000)		$ 500,000,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			(42,778)
Stock-based compensation, net of tax			$ 2,000,000	1,000,000
Net earnings (loss) attributable to Celanese Corporation	546,000,000				546,000,000
Common stock dividends					148,000,000
Other comprehensive income (loss), net of tax	(20,000,000)					(20,000,000)
Balance as of the end of the period, shares at Jun. 30, 2019		123,740,349	45,170,482
Stockholders' Equity Attributable to Noncontrolling Interest at Dec. 31, 2018	395,000,000						395,000,000
Net earnings (loss) attributable to noncontrolling interests	2,000,000						2,000,000
(Distributions to) contributions from noncontrolling interests							7,000,000
Stockholders' Equity Attributable to Noncontrolling Interest at Jun. 30, 2019	390,000,000						390,000,000
Total Celanese Corporation stockholders' equity at Jun. 30, 2019	2,864,000,000	$ 0	$ (3,347,000,000)	233,000,000	6,245,000,000	(267,000,000)
Balance as of the end of the period at Jun. 30, 2019	3,254,000,000
Balance as of the beginning of the period, shares at Mar. 31, 2019		126,612,492	42,285,459
Total Celanese Corporation stockholders' equity at Mar. 31, 2019		$ 0	$ (3,048,000,000)	224,000,000	6,114,000,000	(243,000,000)
Stock option exercises, shares		4,108
Stock option exercises		$ 0		0
Purchases of treasury stock, shares		(2,917,864)
Purchases of treasury stock		$ 0
Stock awards, shares		41,613
Stock awards		$ 0
Purchases of treasury stock, shares			2,917,864
Purchases of treasury stock, including related fees			$ 300,000,000
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures			(32,841)
Stock-based compensation, net of tax			$ 1,000,000	9,000,000
Net earnings (loss) attributable to Celanese Corporation	209,000,000				209,000,000
Common stock dividends					78,000,000
Other comprehensive income (loss), net of tax	(24,000,000)					(24,000,000)
Balance as of the end of the period, shares at Jun. 30, 2019		123,740,349	45,170,482
Stockholders' Equity Attributable to Noncontrolling Interest at Mar. 31, 2019							392,000,000
Net earnings (loss) attributable to noncontrolling interests	1,000,000						1,000,000
(Distributions to) contributions from noncontrolling interests							3,000,000
Stockholders' Equity Attributable to Noncontrolling Interest at Jun. 30, 2019	390,000,000						$ 390,000,000
Total Celanese Corporation stockholders' equity at Jun. 30, 2019	2,864,000,000	$ 0	$ (3,347,000,000)	$ 233,000,000	$ 6,245,000,000	$ (267,000,000)
Balance as of the end of the period at Jun. 30, 2019	$ 3,254,000,000