Restructuring and Asset Related Charges DowDuPont Cost Synergy Program (Details) - USD ($) $ in Millions		3 Months Ended																4 Months Ended	8 Months Ended	12 Months Ended			28 Months Ended
		Dec. 31, 2019		Sep. 30, 2019	[1]	Jun. 30, 2019	[1]	Mar. 31, 2019		Dec. 31, 2018		Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2019		Dec. 31, 2018	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net		$ 55	[1]	$ 46		$ 60		$ 61	[1]	$ 228	[1]	$ 235		$ 101		$ 130		$ 270	$ 12	$ 222		$ 694
DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																		269		92		484	$ 845
Restructuring Reserve, Beginning Balance								215												215
Payments for Restructuring																				(209)
Asset write-offs																				(29)
Restructuring Reserve, Ending Balance		69								215										69		215	69
DowDuPont Cost Synergy Program [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																		135		(7)		191	319
Restructuring Reserve, Beginning Balance								154												154
Payments for Restructuring																				(118)
Asset write-offs																				0
Restructuring Reserve, Ending Balance		29								154										29		154	29
DowDuPont Cost Synergy Program [Member] | Costs Related To Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																		40		69	[2]	84	193
Restructuring Reserve, Beginning Balance	[2]							61												61
Payments for Restructuring	[2]																			(90)
Asset write-offs	[2]																			0
Restructuring Reserve, Ending Balance	[2]	40								61										40		61	40
DowDuPont Cost Synergy Program [Member] | Asset Related Charges [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																		94		30		209	333
Restructuring Reserve, Beginning Balance								$ 0												0
Payments for Restructuring																				(1)
Asset write-offs																				(29)
Restructuring Reserve, Ending Balance		$ 0								$ 0										0		0	$ 0
DowDuPont Cost Synergy Program [Member] | Seed [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																		133		66		237
DowDuPont Cost Synergy Program [Member] | Crop Protection [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																		(2)		27		57
DowDuPont Cost Synergy Program [Member] | Corporate Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Asset Related Charges - Net																		$ 138		$ (1)		$ 190

[1] Note 7 - Restructuring and Asset Related Charges - Net, Note 5 - Divestitures and Other Transactions, and Note 15 - Goodwill and Other Intangible Assets, for additional information related to integration and separation costs, restructuring and asset related charges - net, discontinued operations, and goodwill impairment charge, respectively.

[2] Relates primarily to contract terminations charges.