Restructuring and Asset Related Charges DowDuPont Cost Synergy Program (Details) - USD ($) $ in Millions		3 Months Ended			17 Months Ended
		Mar. 31, 2019		Mar. 31, 2018	Mar. 31, 2019	Nov. 01, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		$ 55		$ 97
DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance		247
Restructuring and Asset Related Charges - Net		56	[1]	97	$ 565
Payments for Restructuring		(50)
Asset write-offs and adjustments		(15)
Restructuring Reserve, Ending Balance		238			238
DowDuPont Cost Synergy Program [Member] | Restructuring and Asset Related Charges - Net [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net	[1]	55
DowDuPont Cost Synergy Program [Member] | Nonoperating Income (Expense) [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net	[1]	1
DowDuPont Cost Synergy Program [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost						$ 695
DowDuPont Cost Synergy Program [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost						755
DowDuPont Cost Synergy Program [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance		229
Restructuring and Asset Related Charges - Net		40		68	412
Payments for Restructuring		(43)
Asset write-offs and adjustments		0
Restructuring Reserve, Ending Balance		226			226
DowDuPont Cost Synergy Program [Member] | Employee Severance [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost						420
DowDuPont Cost Synergy Program [Member] | Employee Severance [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost						440
DowDuPont Cost Synergy Program [Member] | Costs Related To Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance		18
Restructuring and Asset Related Charges - Net		0		29	71
Payments for Restructuring		(7)
Asset write-offs and adjustments		0
Restructuring Reserve, Ending Balance		11			11
DowDuPont Cost Synergy Program [Member] | Costs Related To Contract Termination [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost						125
DowDuPont Cost Synergy Program [Member] | Costs Related To Contract Termination [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost						145
DowDuPont Cost Synergy Program [Member] | Asset Related Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance		0
Restructuring and Asset Related Charges - Net		16		$ 0	82
Payments for Restructuring		0
Asset write-offs and adjustments		(15)
Restructuring Reserve, Ending Balance		$ 1			$ 1
DowDuPont Cost Synergy Program [Member] | Asset Related Charges [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost						150
DowDuPont Cost Synergy Program [Member] | Asset Related Charges [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost						$ 170

[1] The charge for the three months ended March 31, 2019 includes $55 million which was recognized in restructuring and asset related charges - net and $1 million which was recognized in sundry income - net in the company's Condensed Consolidated Statement of Operations.