Goodwill and Other Intangible Assets Goodwill (Details) - USD ($) $ in Millions	3 Months Ended		4 Months Ended	8 Months Ended	12 Months Ended
	Sep. 30, 2018	[1]	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2018	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, Beginning Balance					$ 45,589
Goodwill, Ending Balance			$ 45,589		40,686
Merger with Dow [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance			45,497
Goodwill, Measurement Period Adjustments					392
Goodwill, Ending Balance				$ 45,497
Predecessor [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance			4,543	4,169
Currency Translation Adjustment				176
Other Goodwill Adjustments and Acquisitions				198
Goodwill Impairment Charge				0		$ 0
Goodwill, Ending Balance				4,543		$ 4,169
Successor [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance			45,105		45,589
Currency Translation Adjustment			(234)		(806)
Goodwill Impairment Charge	$ (4,503)		0		(4,503)
Goodwill, Ending Balance			45,589	$ 45,105	40,686
Successor [Member] | H&N Business [Member]
Goodwill [Line Items]
Goodwill Recognized for H&N Acquisition			$ 718
Goodwill, Measurement Period Adjustments					14
Successor [Member] | Merger with Dow [Member]
Goodwill [Line Items]
Goodwill, Measurement Period Adjustments					$ 392

[1] See Note 14 for additional information