Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss	Unearned ESOP Shares [Member]	Dow Inc. [Member] Retained Earnings [Member]	The Dow Chemical Company	The Dow Chemical Company Common Stock [Member]	The Dow Chemical Company Additional Paid-in Capital [Member]	The Dow Chemical Company Retained Earnings [Member]	The Dow Chemical Company Accumulated Other Comprehensive Loss	The Dow Chemical Company Unearned ESOP Shares [Member]	The Dow Chemical Company Noncontrolling Interests
Total Equity, Beginning at Dec. 31, 2019		$ 8	$ 7,325	$ 17,045	$ (10,246)	$ (91)			$ 0	$ 7,333	$ 17,313	$ (10,246)	$ (91)
Stock Issued										53
Stock-based compensation and allocation of ESOP shares			119			34				119			34
Net income available for The Dow Chemical Company common stockholder	$ (18)			(11)							(11)
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees							$ (1,685)
Other				10							(11)
Other comprehensive income	305				305			$ 305				305
Total Equity, Ending at Sep. 30, 2020	12,932	8	7,497	15,472	(9,941)	(57)		13,691	0	7,505	15,606	(9,941)	(57)	$ 578
Total Equity, Beginning at Jun. 30, 2020		8	7,431	16,017	(10,225)	(69)			0	7,439	16,147	(10,225)	(69)
Stock Issued										23
Stock-based compensation and allocation of ESOP shares			43			12				43			12
Net income available for The Dow Chemical Company common stockholder	(28)			(25)							(25)
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees							(513)
Other				2							(3)
Other comprehensive income	284				284			284				284
Total Equity, Ending at Sep. 30, 2020	12,932	8	7,497	15,472	(9,941)	(57)		13,691	0	7,505	15,606	(9,941)	(57)	578
The Dow Chemical Company’s stockholders’ equity	12,354							13,113
The Dow Chemical Company’s stockholders’ equity	12,435							12,999
Total Equity, Beginning at Dec. 31, 2020	13,005	8	7,595	16,361	(10,855)	(49)		13,569	0	7,603	16,300	(10,855)	(49)
Stock Issued										211
Stock-based compensation and allocation of ESOP shares			182			25				182			25
Net income available for The Dow Chemical Company common stockholder	4,552			4,575							4,576
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees							(2,361)
Other				18							(18)
Other comprehensive income	1,190				1,190			1,190				1,190
Total Equity, Ending at Sep. 30, 2021	17,028	8	7,988	19,357	(9,665)	(24)		17,393	0	7,996	18,497	(9,665)	(24)	589
Total Equity, Beginning at Jun. 30, 2021		8	7,898	18,200	(9,676)	(32)			0	7,906	17,745	(9,676)	(32)
Stock Issued										11
Stock-based compensation and allocation of ESOP shares			79			8				79			8
Net income available for The Dow Chemical Company common stockholder	1,675			1,683							1,679
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees							$ (919)
Other				8							(8)
Other comprehensive income	11				11			11				11
Total Equity, Ending at Sep. 30, 2021	17,028	$ 8	$ 7,988	$ 19,357	$ (9,665)	$ (24)		17,393	$ 0	$ 7,996	$ 18,497	$ (9,665)	$ (24)	$ 589
The Dow Chemical Company’s stockholders’ equity	$ 16,439							$ 16,804