Dow Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 90	$ 1,364	$ 691	$ 2,803
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on investments	33	(14)	100	(39)
Cumulative translation adjustments	67	(470)	36	(94)
Pension and other postretirement benefit plans	106	124	247	250
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(204)	118	(279)	124
Other Comprehensive Income (Loss), Net of Tax	2	(242)	104	241
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	92	1,122	795	3,044
Comprehensive income (loss) attributable to noncontrolling interests, net of tax	21	(1)	72	27
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 71	$ 1,123	$ 723	$ 3,017