Inventories Narrative (Details) - Successor [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended	4 Months Ended
	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2017	Sep. 01, 2017
Inventory [Line Items]
Business Combination, Fair Value Step-Up Of Acquired Inventory, Amount recognized in Cost of Goods sold	$ (360)	$ (1,109)	$ (1,469)
Merger with Dow [Member]
Inventory [Line Items]
Business Combination, Fair Value Step Up Of Acquired Inventory				$ 3,842
Business Combination, Fair Value Step-Up Of Acquired Inventory, Amount recognized in Cost of Goods sold			$ (1,434)