Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 1,377	$ 915
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on investments	(25)	17
Cumulative translation adjustments	376	239
Pension and other postretirement benefit plans	126	102
Derivative instruments	6	(50)
Total other comprehensive income	483	308
Comprehensive income	1,860	1,223
Comprehensive income attributable to noncontrolling interests, net of tax	28	53
Comprehensive income attributable to The Dow Chemical Company	$ 1,832	$ 1,170

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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