Restructuring and Other Charges - Schedule of Restructuring and Related Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Restructuring Cost and Reserve [Line Items]
Total cash charges	$ 4	$ 33	$ 15	$ 65
Total non-cash charges	0	9	3	63
Total restructuring and other charges	4	42	18	128
Botlek closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	2	33	8	65
Total non-cash charges	0	9	3	63
Total restructuring and other charges	2	42	11	128
Fuzhou closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	2		7
Total non-cash charges	0		0
Total restructuring and other charges	2		7
Severance and employee benefits
Restructuring Cost and Reserve [Line Items]
Total cash charges	2	9	6	17
Severance and employee benefits \| Botlek closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	1	9	2	17
Severance and employee benefits \| Fuzhou closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	1		4
Idling Activities
Restructuring Cost and Reserve [Line Items]
Total cash charges	2	24	8	30
Idling Activities \| Botlek closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	1	24	5	30
Idling Activities \| Fuzhou closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	1		3
Asset retirement obligation adjustments
Restructuring Cost and Reserve [Line Items]
Total cash charges	0	0	0	11
Asset retirement obligation adjustments \| Botlek closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	0	0	0	11
Asset retirement obligation adjustments \| Fuzhou closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	0		0
Environmental liability
Restructuring Cost and Reserve [Line Items]
Total cash charges	0	0	0	0
Environmental liability \| Botlek closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	0	0	0	0
Environmental liability \| Fuzhou closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	0		0
Contract abandonment and other changes
Restructuring Cost and Reserve [Line Items]
Total cash charges	0	0	1	7
Contract abandonment and other changes \| Botlek closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	0	0	1	7
Contract abandonment and other changes \| Fuzhou closure
Restructuring Cost and Reserve [Line Items]
Total cash charges	0		0
Asset disposal
Restructuring Cost and Reserve [Line Items]
Total non-cash charges	0	9	3	62
Asset disposal \| Botlek closure
Restructuring Cost and Reserve [Line Items]
Total non-cash charges	0	9	3	62
Asset disposal \| Fuzhou closure
Restructuring Cost and Reserve [Line Items]
Total non-cash charges	0		0
Other non-cash charges
Restructuring Cost and Reserve [Line Items]
Total non-cash charges	0	0	0	1
Other non-cash charges \| Botlek closure
Restructuring Cost and Reserve [Line Items]
Total non-cash charges	0	$ 0	0	$ 1
Other non-cash charges \| Fuzhou closure
Restructuring Cost and Reserve [Line Items]
Total non-cash charges	$ 0		$ 0