Dow Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 347	$ 1,049	$ 1,038	$ 3,852
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on investments	11	8	111	(31)
Cumulative translation adjustments	(216)	(98)	(180)	(192)
Pension and other postretirement benefit plans	108	123	355	373
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(134)	208	(413)	332
Other Comprehensive Income (Loss), Net of Tax	(231)	241	(127)	482
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	116	1,290	911	4,334
Comprehensive income (loss) attributable to noncontrolling interests, net of tax	7	31	79	58
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 109	$ 1,259	$ 832	$ 4,276