Restructuring and related activities (2025 Restructuring Program) (Details)	3 Months Ended			6 Months Ended
	Jun. 30, 2025 USD ($)	Mar. 31, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	$ 591,000,000		$ 0	$ 799,000,000	$ 45,000,000
2025 Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related workforce reduction	1,500			1,500
Restructuring and asset related charges - net	$ 591,000,000	$ 207,000,000
Restructuring Reserve, Settled without Cash	(437,000,000)
Payments for Restructuring	(16,000,000)
Restructuring Reserve	345,000,000	207,000,000		$ 345,000,000
Restructuring Charges				798,000,000
Asset Retirement Obligation, Liabilities Incurred	111,000,000
2025 Program \| Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	154,000,000	207,000,000
Restructuring Reserve, Settled without Cash	0
Payments for Restructuring	(16,000,000)
Restructuring Reserve	345,000,000	207,000,000		345,000,000
Restructuring Charges				361,000,000
2025 Program \| Asset write-downs and write-offs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	334,000,000	0
Restructuring Reserve, Settled without Cash	(334,000,000)
Payments for Restructuring	0
Restructuring Reserve	0	0		0
Restructuring Charges	334,000,000			334,000,000
2025 Program \| Costs Associated with Exit and Disposal Activities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	103,000,000	0
Restructuring Reserve, Settled without Cash	(103,000,000)
Payments for Restructuring	0
Restructuring Reserve	0	0		0
Restructuring Charges				103,000,000
2025 Program \| Costs Associated with Exit and Disposal Activities [Member] \| Additional Cash Expenditures
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	60,000,000			60,000,000
2025 Program \| Restructuring Implementation Costs
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring	(5,000,000)			(5,000,000)
Restructuring Charges	5,000,000			5,000,000
2025 Program \| Restructuring Implementation Costs \| Additional Cash Expenditures
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	225,000,000			225,000,000
Segment Reporting, Reconciling Item, Corporate Nonsegment \| 2025 Program
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	197,000,000	207,000,000
Segment Reporting, Reconciling Item, Corporate Nonsegment \| 2025 Program \| Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	154,000,000	207,000,000
Segment Reporting, Reconciling Item, Corporate Nonsegment \| 2025 Program \| Asset write-downs and write-offs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	43,000,000	0
Segment Reporting, Reconciling Item, Corporate Nonsegment \| 2025 Program \| Costs Associated with Exit and Disposal Activities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	0	$ 0
Segment Reporting, Reconciling Item, Corporate Nonsegment \| 2025 Program \| Restructuring Implementation Costs
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	5,000,000			5,000,000
Packaging & Specialty Plastics [Member] \| 2025 Program
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	158,000,000
Packaging & Specialty Plastics [Member] \| 2025 Program \| Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	0
Packaging & Specialty Plastics [Member] \| 2025 Program \| Asset write-downs and write-offs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	81,000,000
Packaging & Specialty Plastics [Member] \| 2025 Program \| Costs Associated with Exit and Disposal Activities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	77,000,000
Industrial Intermediates & Infrastructure [Member] \| 2025 Program
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	89,000,000
Industrial Intermediates & Infrastructure [Member] \| 2025 Program \| Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	0
Industrial Intermediates & Infrastructure [Member] \| 2025 Program \| Asset write-downs and write-offs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	63,000,000
Industrial Intermediates & Infrastructure [Member] \| 2025 Program \| Costs Associated with Exit and Disposal Activities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	26,000,000
Performance Materials & Coatings [Member] \| 2025 Program
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	147,000,000
Performance Materials & Coatings [Member] \| 2025 Program \| Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	0
Performance Materials & Coatings [Member] \| 2025 Program \| Asset write-downs and write-offs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	147,000,000
Performance Materials & Coatings [Member] \| 2025 Program \| Costs Associated with Exit and Disposal Activities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and asset related charges - net	0
Accrued and Other Current Liabilities [Member] \| 2025 Program
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	178,000,000			178,000,000
Other Noncurrent Obligations [Member] \| 2025 Program
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 167,000,000			$ 167,000,000

DOW INC. 10-Q