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]	Noncontrolling Interests	The Dow Chemical Company [Domain]	The Dow Chemical Company [Domain] Common Stock [Member]	The Dow Chemical Company [Domain] Additional Paid-in Capital [Member]	The Dow Chemical Company [Domain] Retained Earnings [Member]	The Dow Chemical Company [Domain] Accumulated Other Comprehensive Loss	The Dow Chemical Company [Domain] Unearned ESOP Shares [Member]	The Dow Chemical Company [Domain] Noncontrolling Interests	DowDuPont [Member] Retained Earnings [Member]	Dow Inc. [Member] Retained Earnings [Member]
Total Equity, Beginning at Dec. 31, 2018		$ 0	$ 7,042	$ 35,460	$ (9,885)	$ (134)			$ 0	$ 7,042	$ 35,460	$ (9,885)	$ (134)
Stock Issued										11
Stock Issued During Period, Value, Parent Company Stock - DWDP			28							28
Stock-based compensation and allocation of ESOP shares			202			41				202			41
Adjustments to Additional Paid in Capital, Other										(38)
Net income available for The Dow Chemical Company common stockholder				964							1,068
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees				(535)											$ (535)	$ 0
Impact of common control transaction 2	$ (1,935)			(14,861)	(793)		$ (353)	$ (61)			(16,022)	(793)
Other			37	11							(11)
Other comprehensive income	(127)				(127)			(127)				(127)
Total Equity, Ending at Sep. 30, 2019	17,986	7	7,239	19,873	(9,219)	(95)		18,367	0	7,245	19,849	(9,219)	(95)	$ 587
ESOP shares acquired						(2)							(2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Period Increase (Decrease) | Adjustments for New Accounting Pronouncement				(111)							(111)
Total Equity, Beginning at Jun. 30, 2019		7	7,186	20,110	(8,988)	(99)			0	7,192	19,575	(8,988)	(99)
Stock Issued										5
Stock Issued During Period, Value, Parent Company Stock - DWDP			0							0
Stock-based compensation and allocation of ESOP shares			55			6				55			6
Adjustments to Additional Paid in Capital, Other										(7)
Net income available for The Dow Chemical Company common stockholder				333							310
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees				0							0					0
Impact of common control transaction 2				(50)	0		0				(32)	0
Other			7	4							(4)
Other comprehensive income	(231)				(231)			(231)				(231)
Total Equity, Ending at Sep. 30, 2019	17,986	7	7,239	19,873	(9,219)	(95)		18,367	0	7,245	19,849	(9,219)	(95)	587
ESOP shares acquired						(2)							(2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Period Increase (Decrease) | Adjustments for New Accounting Pronouncement				0							0
The Dow Chemical Company’s stockholders’ equity	17,399							17,780
The Dow Chemical Company’s stockholders’ equity	13,541							14,309
Total Equity, Beginning at Dec. 31, 2019	14,094	8	7,325	17,045	(10,246)	(91)		14,862	0	7,333	17,313	(10,246)	(91)
Stock Issued										53
Stock Issued During Period, Value, Parent Company Stock - DWDP			0							0
Stock-based compensation and allocation of ESOP shares			119			34				119			34
Adjustments to Additional Paid in Capital, Other										0
Net income available for The Dow Chemical Company common stockholder				(11)							(11)
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees				0											$ 0	(1,685)
Impact of common control transaction 2	0			0	0		0	0			0	0
Other			0	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
ESOP shares acquired						0							0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Period Increase (Decrease) | Adjustments for New Accounting Pronouncement				0							0
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 Issued During Period, Value, Parent Company Stock - DWDP			0							0
Stock-based compensation and allocation of ESOP shares			43			12				43			12
Adjustments to Additional Paid in Capital, Other										0
Net income available for The Dow Chemical Company common stockholder				(25)							(25)
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees				0							0					$ (513)
Impact of common control transaction 2				0	0		$ 0				0	0
Other			0	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
ESOP shares acquired						$ 0							$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders' Equity, Period Increase (Decrease) | Adjustments for New Accounting Pronouncement				$ 0							$ 0
The Dow Chemical Company’s stockholders’ equity	$ 12,354							$ 13,113