Goodwill and Intangible Assets, Net (Schedule of Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024		Sep. 30, 2025		Dec. 31, 2025		Dec. 31, 2024		Dec. 31, 2023
Goodwill
Goodwill, beginning balance				$ 5,387	[1]	$ 5,387	[1]	$ 6,977
Transfer to assets held for sale (Note 4)						(154)
Impairment losses						(1,140)		(1,517)		$ 0
Exchange rate changes						78		(73)
Goodwill, ending balance		$ 5,387	[1]			$ 4,171	[2]	$ 5,387	[1]	6,977
Goodwill, Impairment Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]						Other Nonrecurring (Income) Expense		Other Nonrecurring (Income) Expense
Engineered Materials
Goodwill
Goodwill, beginning balance				5,025	[1]	$ 5,025	[1]	$ 6,602
Transfer to assets held for sale (Note 4)						(154)
Impairment losses	$ (1,100)	(1,500)		(1,000)		(1,140)		(1,517)
Exchange rate changes						51		(60)
Goodwill, ending balance		5,025	[1]			3,782	[2]	5,025	[1]	6,602
Goodwill, Impaired, Accumulated Impairment Loss		(1,500)				(2,700)		(1,500)
Acetyl Chain
Goodwill
Goodwill, beginning balance				$ 362	[1]	362	[1]	375
Transfer to assets held for sale (Note 4)						0
Impairment losses						0		0
Exchange rate changes						27		(13)
Goodwill, ending balance		$ 362	[1]			$ 389	[2]	$ 362	[1]	$ 375

[1] Includes accumulated impairment losses of $1.5 billion in the Engineered Materials segment.

[2] Includes accumulated impairment losses of $2.7 billion in the Engineered Materials segment.