Business Combinations (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions			1 Months Ended
		Aug. 31, 2017	Sep. 30, 2017
Business Acquisition [Line Items]
Business Combination, Consideration Transferred		$ 74,680
Business Combination, Consideration Transferred, Equity Interests Issued And Issuable, Converted But Not Yet Earned		144
$4.50 Series preferred stock [Member]
Business Acquisition [Line Items]
Preferred Stock, Par or Stated Value Per Share			$ 4.50
$3.50 Series preferred stock [Member]
Business Acquisition [Line Items]
Preferred Stock, Par or Stated Value Per Share			$ 3.50
Merger with Dow [Domain]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Inventory, Finished Products		5,115
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Inventory, Semi-finished products		3,066
Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed Inventory, Raw Materials		705
Business Combination, Fair Value Step-Up Of Acquired Inventory Including Discontinued Operations			$ 429
Business Combination, Fair Value Step-Up Of Acquired Inventory, Continuing Operations			360
Disposal Group, Including Discontinued Operations, Fair Value Step-Up Of Acquired Inventory			$ 69
Property, plant and equipment - net		12,122
Goodwill	[1]	45,501
Adjustment to establish valuation allowance		172
Adjustment to reflect change in reinvestment strategy		$ 546
E I DuPont de Nemours & Co [Member]
Business Acquisition [Line Items]
Common Stock, Par or Stated Value Per Share		$ 0.30
DowDuPont [Member]
Business Acquisition [Line Items]
Common Stock, Par or Stated Value Per Share		$ 0.01
Land and Land Improvements [Member] | Merger with Dow [Domain]
Business Acquisition [Line Items]
Property, plant and equipment - net		$ 967
Building [Member] | Merger with Dow [Domain]
Business Acquisition [Line Items]
Property, plant and equipment - net		2,615
Machinery and Equipment [Member] | Merger with Dow [Domain]
Business Acquisition [Line Items]
Property, plant and equipment - net		7,540
Construction in Progress [Member] | Merger with Dow [Domain]
Business Acquisition [Line Items]
Property, plant and equipment - net		1,000
Equity and Incentive Plan [Member] | Merger with Dow [Domain]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Equity Interests Issued And Issuable, Converted But Not Yet Earned		$ 144
Equity and Incentive Plan [Member] | Common Stock [Member] | Merger with Dow [Domain]
Business Acquisition [Line Items]
DuPont to DowDuPont share exchange ratio		1.2820

[1] See Note 11 for additional information.