COMMITMENTS AND CONTINGENT LIABILITIES (Rohm and Haas Pension Plan Matters) (Narrative) (Details) (Rohm And Haas [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Apr. 02, 2009
Rohm And Haas [Member]
Loss Contingencies [Line Items]
Pension liability from Rohm and Haas acquisition	$ 189	$ 186	$ 185

The amount of pension liabilities assumed (as defined) which have been recognized as of the acquisition date.

No definition available.

Name:	dow_BusinessCombinationRecognizedIdentifiableAssetAcquiredLiabilitiesAssumedPensionLiability
Namespace Prefix:	dow_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant