Dow Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 258	$ 601
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on investments	(100)	67
Cumulative translation adjustments	(163)	(31)
Pension and other postretirement benefit plans	142	141
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(162)	(75)
Other Comprehensive Income (Loss), Net of Tax	(283)	102
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	(25)	703
Comprehensive income attributable to noncontrolling interests, net of tax	19	51
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ (44)	$ 652