2017 DWDP Cost Synergy Program (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Nov. 01, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	$ 165	$ (1)
DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost				$ 1,300
Restructuring, Settlement and Impairment Provisions	163		$ 687
Restructuring Reserve, Settled without Cash	(48)		(287)
Payments for Restructuring	(74)		(51)
Restructuring Reserve	390		349
Restructuring Reserve, Accrual Adjustment	163
Employee Severance [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	104		357
Restructuring Reserve, Settled without Cash	0		0
Payments for Restructuring	(73)		(51)
Restructuring Reserve	337		306
Restructuring Reserve, Accrual Adjustment	104
Asset write-downs and write-offs [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	48		287
Restructuring Reserve, Settled without Cash	(48)		(287)
Payments for Restructuring	0		0
Restructuring Reserve	0		0
Restructuring Reserve, Accrual Adjustment	48
Costs Associated with Exit and Disposal Activities [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	11		43
Restructuring Reserve, Settled without Cash	0		0
Payments for Restructuring	(1)		0
Restructuring Reserve	53		43
Restructuring Reserve, Accrual Adjustment	11
Minimum [Member] | Employee Severance [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost				525
Minimum [Member] | Asset write-downs and write-offs [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost				400
Minimum [Member] | Costs Associated with Exit and Disposal Activities [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost				290
Maximum [Member] | Employee Severance [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost				575
Maximum [Member] | Asset write-downs and write-offs [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost				440
Maximum [Member] | Costs Associated with Exit and Disposal Activities [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost				$ 310
Accrued and Other Current Liabilities [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	260		231
Other Noncurrent Liabilities [Member] | DowDuPont Cost Synergy Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 130		$ 118