Other (Charges) Gains, Net (Schedule of Restructuring Reserves) (Details) - Employee Termination Benefits [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Restructuring Reserve [Roll Forward]
Reserve as of the beginning of the period	$ 13	$ 4
Additions	23	24
Cash payments	(22)	(14)
Other changes	(3)	1
Reserve as of the end of the period	11	13
Total	11	13
Other [Member]
Restructuring Reserve [Roll Forward]
Reserve as of the beginning of the period	5	0
Additions	10	9
Cash payments	(12)	(4)
Other changes	(1)	0
Reserve as of the end of the period	2	5
Total	2	5
Engineered Materials [Member]
Restructuring Reserve [Roll Forward]
Reserve as of the beginning of the period	5	0
Additions	12	10
Cash payments	(7)	(5)
Other changes	(2)	0
Reserve as of the end of the period	8	5
Total	8	5
Acetate Tow [Member]
Restructuring Reserve [Roll Forward]
Reserve as of the beginning of the period	3	2
Additions	0	4
Cash payments	(2)	(3)
Other changes	0	0
Reserve as of the end of the period	1	3
Total	1	3
Acetyl Chain [Member]
Restructuring Reserve [Roll Forward]
Reserve as of the beginning of the period	0	2
Additions	1	1
Cash payments	(1)	(2)
Other changes	0	1
Reserve as of the end of the period	0	0
Total	$ 0	$ 0