Note 7 - Restructuring, Impairment and Plant Closing Costs - Reserves for Restructuring, Impairment and Plant Closing Costs By Segment and Initiative (Details) $ in Millions	3 Months Ended
Mar. 31, 2026 USD ($)
Balance	$ 45
Charges, net	5
Payments	(12)
Balance	38
Current portion of restructuring reserves	36
Long-term portion of restructuring reserves	2
Polyurethanes [Member]
Balance	37
Charges, net	1
Payments	(11)
Balance	27
Current portion of restructuring reserves	27
Long-term portion of restructuring reserves	0
Performance Products [Member]
Balance	5
Charges, net	0
Payments	(1)
Balance	4
Current portion of restructuring reserves	4
Long-term portion of restructuring reserves	0
Advanced Materials [Member]
Balance	3
Charges, net	4
Payments	0
Balance	7
Current portion of restructuring reserves	5
Long-term portion of restructuring reserves	$ 2

Carrying amount as of the balance sheet date of known and estimated obligations associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, which are expected to be paid in the next twelve months or in the normal operating cycle if longer. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482017/420-10-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4.b.2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Name:	us-gaap_RestructuringReserveCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant