Revenue Recognition - Disaggregation of net sales (Details) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
		Sep. 30, 2021		Sep. 30, 2020		Sep. 30, 2021		Sep. 30, 2020
Revenue, Major Customer [Line Items]
Net sales		$ 2,266		$ 1,411		$ 6,262		$ 4,064
Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales	[1]	1,454		756		3,866		2,170
Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		684		526		2,011		1,509
Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		128		129		385		385
Intersegment Eliminations [Member]
Revenue, Major Customer [Line Items]
Net sales		(35)	[2]	(20)	[2]	(88)	[3]	(67)	[3]
Intersegment Eliminations [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		35		20		88		67
North America [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		405		246		1,046		728
North America [Member] | Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		194		147		546		420
North America [Member] | Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		24		24		77		72
Europe and Africa [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		458		251		1,188		753
Europe and Africa [Member] | Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		282		222		882		665
Europe and Africa [Member] | Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		64		64		204		203
Asia Pacific [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		540		243		1,530		640
Asia Pacific [Member] | Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		185		141		518		381
Asia Pacific [Member] | Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		39		40		99		101
South America [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		51		16		102		49
South America [Member] | Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		23		16		65		43
South America [Member] | Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		$ 1		$ 1		$ 5		$ 9

[1] Excludes intersegment sales of $35 million and $20 million for the three months ended September 30, 2021 and 2020, respectively. Excludes intersegment sales of $88 million and $67 million for the nine months ended September 30, 2021 and 2020, respectively.

[2] Includes intersegment sales primarily related to the Acetyl Chain.

[3] Includes intersegment sales primarily related to the Acetyl Chain.