TDCC Consolidated Statements of Equity Statement - USD ($) $ in Millions	Total	Common Stock	Add'l Paid-in Capital	Retained Earnings [Member]	Accumulated Other Comprehensive Loss	Unearned ESOP	The Dow Chemical Company	The Dow Chemical Company Common Stock	The Dow Chemical Company Add'l Paid-in Capital	The Dow Chemical Company Retained Earnings [Member]	The Dow Chemical Company Accumulated Other Comprehensive Loss	The Dow Chemical Company Unearned ESOP	Dow Inc. [Member] The Dow Chemical Company Add'l Paid-in Capital	Dow Inc. [Member] The Dow Chemical Company Retained Earnings [Member]	DowDuPont The Dow Chemical Company Add'l Paid-in Capital	DowDuPont The Dow Chemical Company Retained Earnings [Member]
Beginning balance at Dec. 31, 2017		$ 0	$ 6,553	$ 33,742	$ (8,591)	$ (189)		$ 0	$ 6,553	$ 33,742	$ (8,591)	$ (189)
Issuance of parent company stock			112										$ 0		$ 112
Stock-based compensation and allocation of ESOP shares			377			55			377			55
Other			0	19					0	(19)
Net income (loss) available for The Dow Chemical Company common stockholder	$ 4,641			4,641			$ 4,641			4,641
Dividends to parent				(3,711)										$ (3,711)		$ 0
Settlements and transfers related to separation from DowDuPont Inc.	240			(182)	0		240			(182)	0
Stockholders' Equity, Period Increase (Decrease) | Adjustments for New Accounting Pronouncement [Member]				989	(1,037)					989	(1,037)
Other comprehensive income (loss)	(257)				(257)						(257)
ESOP shares acquired						0						0
Ending balance at Dec. 31, 2018	33,621	0	7,042	35,460	(9,885)	(134)	33,621	0	7,042	35,460	(9,885)	(134)
The Dow Chemical Company’s stockholder's equity	32,483						32,483
Noncontrolling interests	1,138						1,138
Issuance of parent company stock			28										65		28
Stock-based compensation and allocation of ESOP shares			235			45			235			45
Other			37	14					(37)	(14)
Net income (loss) available for The Dow Chemical Company common stockholder	(1,359)			(1,359)			(1,237)			(1,237)
Dividends to parent				(535)										(535)		(201)
Settlements and transfers related to separation from DowDuPont Inc.	(1,935)			(14,806)	793		61			(16,009)	793
Stockholders' Equity, Period Increase (Decrease) | Adjustments for New Accounting Pronouncement [Member]				(151)	0					(151)	0
Other comprehensive income (loss)	(1,154)				(1,154)						(1,154)
ESOP shares acquired						(2)						(2)
Ending balance at Dec. 31, 2019	14,094	8	7,325	17,045	(10,246)	(91)	14,862	$ 0	7,333	17,313	(10,246)	(91)
The Dow Chemical Company’s stockholder's equity	13,541						14,309
Noncontrolling interests	553						553
Issuance of parent company stock			0										$ 108		$ 0
Stock-based compensation and allocation of ESOP shares			162			42			162			42
Other			0	15					0	(15)
Net income (loss) available for The Dow Chemical Company common stockholder	1,225			1,225			1,235			1,235
Dividends to parent				0										$ 0		$ (2,233)
Settlements and transfers related to separation from DowDuPont Inc.	0			177	0		0			0	0
Stockholders' Equity, Period Increase (Decrease) | Adjustments for New Accounting Pronouncement [Member]				0	0					0	0
Other comprehensive income (loss)	(609)				(609)						(609)
ESOP shares acquired						0						0
Ending balance at Dec. 31, 2020	13,005	$ 8	$ 7,595	$ 16,361	$ (10,855)	$ (49)	13,569		$ 7,603	$ 16,300	$ (10,855)	$ (49)
The Dow Chemical Company’s stockholder's equity	12,435						12,999
Noncontrolling interests	$ 570						$ 570