Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Add'l Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Unearned ESOP	Treasury Stock	Noncontrolling Interests
Beginning balance at Dec. 31, 2014	$ 23,354,000	$ 4,000,000	$ 3,107,000	$ 4,846,000	$ 23,045,000	$ (8,017,000)	$ (325,000)	$ (4,233,000)	$ 931,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income available for The Dow Chemical Company common stockholder	7,345,000				7,345,000
Other comprehensive income (loss)	(650,000)					(650,000)
Dividends to stockholders	(1,942,000)				(1,942,000)
Common stock issued / sold	1,274,000			508,000				766,000
Stock-based compensation and allocation of ESOP shares	(376,000)			(429,000)			53,000
Impact of noncontrolling interests	(122,000)								(122,000)
Treasury stock purchases	(2,688,000)							(2,688,000)
Other	(12,000)			11,000	(23,000)
Ending balance at Dec. 31, 2015	26,183,000	4,000,000	3,107,000	4,936,000	28,425,000	(8,667,000)	(272,000)	(6,155,000)	809,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income available for The Dow Chemical Company common stockholder	3,978,000				3,978,000
Other comprehensive income (loss)	(1,155,000)					(1,155,000)
Dividends to stockholders	(2,037,000)				(2,037,000)
Common stock issued / sold	1,115,000			398,000				717,000
Stock-based compensation and allocation of ESOP shares	(325,000)			(376,000)			51,000
ESOP shares acquired	(18,000)						(18,000)
Impact of noncontrolling interests	433,000								433,000
Treasury stock purchases	(916,000)							(916,000)
Preferred stock converted to common stock	0	(4,000,000)		695,000				4,695,000
Other	(29,000)			(1,000)	(28,000)
Ending balance at Dec. 31, 2016	27,229,000	0	3,107,000	4,262,000	30,338,000	(9,822,000)	(239,000)	(1,659,000)	1,242,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income available for The Dow Chemical Company common stockholder	466,000				466,000
Other comprehensive income (loss)	1,231,000					1,231,000
Dividends to stockholders	(1,673,000)				(1,673,000)
Dividends to parent	(1,056,000)				(1,056,000)
Common stock issued / sold	1,147,000			423,000				724,000
Issuance of parent company stock	66,000			66,000
Stock-based compensation and allocation of ESOP shares	(318,000)			(368,000)			50,000
Impact of noncontrolling interests	(56,000)								(56,000)
Merger impact	0		3,107,000	2,172,000				935,000
Other	(27,000)			(2,000)	(25,000)
Ending balance at Dec. 31, 2017	$ 27,009,000	$ 0	$ 0	$ 6,553,000	$ 28,050,000	$ (8,591,000)	$ (189,000)	$ 0	$ 1,186,000