Dow Consolidated Statements of Income Statement - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net sales	$ 11,882	$ 9,770
Cost of sales	10,062	8,230
Research and development expenses	194	179
Selling, general and administrative expenses	366	334
Amortization of intangibles	101	100
Restructuring and asset related charges - net	0	96
Integration and separation costs	0	65
Equity in earnings (losses) of nonconsolidated affiliates	224	(89)
Sundry income (expense) - net	128	(81)
Interest income	8	15
Interest expense and amortization of debt discount	196	215
Income before income taxes	1,323	396
Provision for income taxes	317	138
Net income	1,006	258
Net income attributable to noncontrolling interests	15	19
Net income available for The Dow Chemical Company common stockholder	$ 991	$ 239
Earnings per common share - basic	$ 1.32	$ 0.32
Earnings per common share - diluted	$ 1.32	$ 0.32
Weighted-average common shares outstanding - basic	744.8	740.2
Weighted-average common shares outstanding - diluted	749.8	742.0