Dow Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (1)	$ 347	$ 40	$ 1,038
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on investments	8	11	(16)	111
Cumulative translation adjustments	91	(216)	(9)	(180)
Pension and other postretirement benefit plans	147	108	430	355
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	38	(134)	(100)	(413)
Other Comprehensive Income (Loss), Net of Tax	284	(231)	305	(127)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	283	116	345	911
Comprehensive income attributable to noncontrolling interests, net of tax	24	7	51	79
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 259	$ 109	$ 294	$ 832