Debt (Schedule of Long-term Debt) (Details) € in Millions, $ in Millions				12 Months Ended
		Dec. 31, 2017 USD ($)		Dec. 31, 2017 USD ($)		Dec. 11, 2017 EUR (€)	Dec. 31, 2016 USD ($)		Sep. 26, 2016 EUR (€)	Jul. 15, 2016 USD ($)	Dec. 31, 2015 USD ($)	[1]	Dec. 31, 2014 USD ($)
Long-Term Debt
Subtotal		$ 3,398		$ 3,398			$ 2,938
Unamortized debt issuance costs		(24)	[1]	(24)	[1]		(27)	[1]			$ (22)		$ (27)
Current installments of long-term debt		(63)		(63)			(27)
Total		3,315		$ 3,315			2,890
Debt Instrument, Redemption Price, Percentage				100.00%
Senior Unsecured Term Loan Due 2021 [Member]
Long-Term Debt
Secured Debt	[2]									$ 500
Senior unsecured notes	[2]	494		$ 494			500
Maturity Date				Jul. 15, 2021
Senior Unsecured Notes Due 2019 [Member]
Long-Term Debt
Senior unsecured notes		$ 360		$ 360			316
Maturity Date				Oct. 15, 2019
Interest Rate		3.25%		3.25%
Senior Unsecured Notes Due 2021 [Member]
Long-Term Debt
Senior unsecured notes		$ 400		$ 400			400
Maturity Date				Jun. 15, 2021
Interest Rate		5.875%		5.875%
Senior Unsecured Notes Due 2022 [Member]
Long-Term Debt
Senior unsecured notes		$ 500		$ 500			500
Maturity Date				Nov. 15, 2022
Interest Rate		4.625%		4.625%
Senior Unsecured Notes Due 2023 [Member]
Long-Term Debt
Senior unsecured notes		$ 897		$ 897			788
Maturity Date				Sep. 26, 2023
Interest Rate		1.125%		1.125%
Debt Instrument, Redemption Price, Percentage				100.00%
Long-term Debt, Gross | €									€ 750
Percentage of Face									99.713%
Senior Unsecured Notes Due 2025 [Member]
Long-Term Debt
Senior unsecured notes		$ 359		$ 359			0
Maturity Date				Dec. 11, 2025
Interest Rate		1.25%		1.25%
Debt Instrument, Redemption Price, Percentage				100.00%
Long-term Debt, Gross | €						€ 300
Percentage of Face						99.81%
Pollution Control and Industrial Revenue Bonds [Member]
Long-Term Debt
Year of maturity, range end				Nov. 01, 2030
Refunding loan for pollution control and industrial revenue bonds [Member]
Long-Term Debt
Pollution control and industrial revenue bonds due at various dates through 2030, interest rates ranging from 5.70% to 6.70%		$ 169		$ 169			$ 170
Year of maturity, range end				Dec. 31, 2030
Bank Loans Acquired from SOFTER [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate, at Point in Time							1.60%
Long-Term Debt
Pollution control and industrial revenue bonds due at various dates through 2030, interest rates ranging from 5.70% to 6.70%		$ 0	[3]	$ 0	[3]		$ 47
Year of maturity, range end		Dec. 31, 2021
Nilit [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate, at Point in Time		1.30%		1.30%
Long-Term Debt
Pollution control and industrial revenue bonds due at various dates through 2030, interest rates ranging from 5.70% to 6.70%		$ 11	[4]	$ 11	[4]		0
Obligations Under Capital Leases [Member]
Long-Term Debt
Year of maturity, range end				Mar. 31, 2054
Obligations under capital leases due at various dates through 2054		208		$ 208			217
Long-term Debt [Member]
Long-Term Debt
Unamortized debt issuance costs	[5]	$ (20)		$ (20)			$ (21)
Minimum [Member] | Pollution Control and Industrial Revenue Bonds [Member]
Long-Term Debt
Interest Rate		5.70%		5.70%
Minimum [Member] | Refunding loan for pollution control and industrial revenue bonds [Member]
Long-Term Debt
Interest Rate		4.05%		4.05%
Maximum [Member] | Pollution Control and Industrial Revenue Bonds [Member]
Long-Term Debt
Interest Rate		6.70%		6.70%
Maximum [Member] | Refunding loan for pollution control and industrial revenue bonds [Member]
Long-Term Debt
Interest Rate		5.00%		5.00%
London Interbank Offered Rate (LIBOR) [Member] | Senior Unsecured Term Loan Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.50%

[1] Includes $4 million, $6 million and $4 million as of December 31, 2017, 2016 and 2015, respectively, related to the Company's revolving credit facility and accounts receivables securitization facility, which are included in noncurrent Other assets in the consolidated balance sheets.

[2] The margin for borrowings under the senior unsecured term loan due 2021 was 1.5% above LIBOR at current Celanese credit ratings.

[3] The weighted average interest rate was 1.6% as of December 31, 2016.

[4] The weighted average interest rate was 1.3% as of December 31, 2017.

[5] Related to the Company's long-term debt, excluding obligations under capital leases.