Revenue Recognition - Disaggregation of net sales (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2021		Jun. 30, 2020		Jun. 30, 2021		Jun. 30, 2020
Revenue, Major Customer [Line Items]
Net sales		$ 2,198		$ 1,193		$ 3,996		$ 2,653
Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales	[1]	1,378		646		2,412		1,414
Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		682		420		1,327		983
Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		138		127		257		256
Intersegment Eliminations [Member]
Revenue, Major Customer [Line Items]
Net sales		(31)	[2]	(16)	[2]	(53)	[3]	(47)	[3]
Intersegment Eliminations [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		31		16		53		47
North America [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		360		208		641		482
North America [Member] | Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		188		111		352		273
North America [Member] | Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		25		27		53		48
Europe and Africa [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		420		236		730		502
Europe and Africa [Member] | Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		304		183		600		443
Europe and Africa [Member] | Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		72		68		140		139
Asia Pacific [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		567		190		990		397
Asia Pacific [Member] | Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		169		117		333		240
Asia Pacific [Member] | Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		38		29		60		61
South America [Member] | Acetyl Chain
Revenue, Major Customer [Line Items]
Net sales		31		12		51		33
South America [Member] | Engineered Materials
Revenue, Major Customer [Line Items]
Net sales		21		9		42		27
South America [Member] | Acetate Tow
Revenue, Major Customer [Line Items]
Net sales		$ 3		$ 3		$ 4		$ 8

[1] Excludes intersegment sales of $31 million and $16 million for the three months ended June 30, 2021 and 2020, respectively. Excludes intersegment sales of $53 million and $47 million for the six months ended June 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.