Supplementary Information Supplementary Information (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	4 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Nov. 02, 2017	Dec. 31, 2016
Successor [Member]
Restricted Cash	$ 558	$ 558
Accrued and other current liabilities	4,384	4,384
Deferred Revenue	2,014	2,014
Compensation and other employee-related costs	857	857
Other noncurrent obligations	1,975	1,975
Accrued benefit costs	7,787	7,787
Stock Repurchase Program, Authorized Amount			$ 4,000
Distributions to DowDuPont	829	(829)
Successor [Member] | DowDuPont [Member]
Accounts Payable, Related Parties	354	354
Successor [Member] | Other Current Assets [Member]
Restricted Cash	$ 558	$ 558
Predecessor [Member]
Accrued and other current liabilities				$ 4,650
Deferred Revenue				2,217
Compensation and other employee-related costs				807
Other noncurrent obligations				12,304
Predecessor [Member] | Pension Plan
Accrued benefit costs				8,092
Predecessor [Member] | Other Post Employment Benefits Plan
Accrued benefit costs				$ 2,554