Restructuring and Asset Related Charges DowDuPont Cost Synergy Program (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended			25 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		$ 46	$ 235	$ 167		$ 466
DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance				215
Restructuring and Asset Related Charges - Net		(8)	109	114		340	$ 866
Payments for Restructuring				(191)
Asset write-offs and adjustments				(30)
Restructuring Reserve, Ending Balance		108		108			108
Employee Severance [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance				154
Restructuring and Asset Related Charges - Net		0	20	14		157	340
Payments for Restructuring				(101)
Asset write-offs and adjustments				0
Restructuring Reserve, Ending Balance		67		67			67
Contract Termination Charges | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance	[1]			61
Restructuring and Asset Related Charges - Net		0	9	69	[1]	46	193
Payments for Restructuring	[1]			(89)
Asset write-offs and adjustments	[1]			0
Restructuring Reserve, Ending Balance	[1]	41		41			41
Asset Related Charges [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance				0
Restructuring and Asset Related Charges - Net		(8)	80	31		137	333
Payments for Restructuring				(1)
Asset write-offs and adjustments				(30)
Restructuring Reserve, Ending Balance		0		0			$ 0
Seed [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		(47)	(190)	(123)		(273)
Seed [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		(7)	64	66		147
Crop Protection [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		1	(30)	(24)		(42)
Crop Protection [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		(1)	30	28		42
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net			(15)	(20)		(151)
Corporate | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		$ 0	$ 15	$ 20		$ 151

[1] Relates primarily to contract terminations charges.