Revenue Recognition - Disaggregation of net sales (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Net sales		$ 2,389	$ 2,611
Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales		1,287	1,378
Acetyl Chain [Member]
Disaggregation of Revenue [Line Items]
Net sales	[1]	1,102	1,233
Intersegment Eliminations
Disaggregation of Revenue [Line Items]
Net sales	[2]	(14)	(28)
Intersegment Eliminations | Acetyl Chain [Member]
Disaggregation of Revenue [Line Items]
Net sales		14	28
North America | Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales		349	372
North America | Acetyl Chain [Member]
Disaggregation of Revenue [Line Items]
Net sales		386	388
Europe and Africa | Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales		388	456
Europe and Africa | Acetyl Chain [Member]
Disaggregation of Revenue [Line Items]
Net sales		385	423
Asia-Pacific | Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales		516	516
Asia-Pacific | Acetyl Chain [Member]
Disaggregation of Revenue [Line Items]
Net sales		307	394
South America | Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales		34	34
South America | Acetyl Chain [Member]
Disaggregation of Revenue [Line Items]
Net sales		$ 24	$ 28

[1] Excludes intersegment sales of $14 million and $28 million for the three months ended March 31, 2025 and 2024, respectively.

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