Goodwill and Intangible Assets, net (Schedule of Goodwill) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2021 USD ($)
Goodwill [Line Items]
As of December 31, 2020	$ 1,166
Exchange rate changes	(23)
As of March 31, 2019	1,143	[1]
Goodwill, Impaired, Accumulated Impairment Loss	0
Engineered Materials
Goodwill [Line Items]
As of December 31, 2020	768
Exchange rate changes	(16)
As of March 31, 2019	752	[1]
Acetate Tow
Goodwill [Line Items]
As of December 31, 2020	149
Exchange rate changes	0
As of March 31, 2019	149	[1]
Acetyl Chain
Goodwill [Line Items]
As of December 31, 2020	249
Exchange rate changes	(7)
As of March 31, 2019	$ 242	[1]

[1] There were no accumulated impairment losses as of June 30, 2021.