Business Combinations Fair Value of Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017	Aug. 31, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Goodwill	$ 40,988	$ 45,589
Merger with Dow [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents			$ 4,005
Marketable securities			2,849
Accounts and notes receivable			7,834
Inventories			8,805
Other current assets			420
Investment in nonconsolidated affiliates			1,596
Assets held for sale - current			3,732
Property, plant and equipment			11,684
Goodwill			45,497
Other intangible assets			27,071
Deferred income tax assets			279
Other assets			2,066
Total assets			115,838
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Short term borrowings and capital lease obligations			5,319
Accounts payable			3,298
Income taxes payable			261
Accrued and other current liabilities			3,517
Liabilities held for sale - current			125
Long-term Debt			9,878
Deferred income tax liabilities			8,259
Pension and other post employment benefits Noncurrent			8,056
Other noncurrent obligations			1,967
Total liabilities			40,680
Noncontrolling interest			239
Preferred stock			239
Fair value of net assets			$ 74,680