Other (Charges) Gains, Net - Schedule of Restructuring Reserve by Type of Cost (Details) - Employee Severance $ in Millions	9 Months Ended
	Sep. 30, 2026 USD ($)
Restructuring Reserve [Roll Forward]
Reserve as of the beginning of the period	$ 31
Additions	76
Cash payments	(28)
Exchange rate changes	(1)
Reserve as of the end of the period	78
Engineered Materials
Restructuring Reserve [Roll Forward]
Reserve as of the beginning of the period	14
Additions	25
Cash payments	(21)
Exchange rate changes	0
Reserve as of the end of the period	18
Acetyl Chain
Restructuring Reserve [Roll Forward]
Reserve as of the beginning of the period	9
Additions	43
Cash payments	(1)
Exchange rate changes	(1)
Reserve as of the end of the period	50
Other
Restructuring Reserve [Roll Forward]
Reserve as of the beginning of the period	8
Additions	8
Cash payments	(6)
Exchange rate changes	0
Reserve as of the end of the period	$ 10