Pension Plans and Other Post Employment Benefit Plans Summary of Fair Value Measurement of Level 3 Pension Plan Assets (Details) - Pension Plan - USD ($) $ in Millions	4 Months Ended		8 Months Ended		12 Months Ended
	Dec. 31, 2017		Aug. 31, 2017		Dec. 31, 2018		Sep. 01, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 20,284				$ 18,918
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	161				330
Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,181				3,037
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27				14
Asset-backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	706				721
Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2				0
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	85				162
Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2				0
Private Market Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14				1
Private Market Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14				1
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	342				336
Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	96				93
Derivative, Asset [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2				206
Derivative, Asset [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0				206
Predecessor [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			$ 19,685					$ 16,656
Predecessor [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			181					198
Actual Return (Loss) on Plan Assets Sold			(19)
Actual Return (Loss) on Plan Assets Still Held			15
Purchases, Sales, and Settlements			0
Assets Transferred into (out of) Level 3			(13)
Predecessor [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			46					39
Actual Return (Loss) on Plan Assets Sold			(20)
Actual Return (Loss) on Plan Assets Still Held			22
Purchases, Sales, and Settlements			(1)
Assets Transferred into (out of) Level 3			6
Predecessor [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			2					0
Actual Return (Loss) on Plan Assets Sold			0
Actual Return (Loss) on Plan Assets Still Held			0
Purchases, Sales, and Settlements			0
Assets Transferred into (out of) Level 3			2
Predecessor [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			0					0
Actual Return (Loss) on Plan Assets Sold			0
Actual Return (Loss) on Plan Assets Still Held			0
Purchases, Sales, and Settlements			0
Assets Transferred into (out of) Level 3			0
Predecessor [Member] | Private Market Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			17					42
Actual Return (Loss) on Plan Assets Sold			0
Actual Return (Loss) on Plan Assets Still Held			(5)
Purchases, Sales, and Settlements			1
Assets Transferred into (out of) Level 3			(21)
Predecessor [Member] | Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			98					98
Actual Return (Loss) on Plan Assets Sold			0
Actual Return (Loss) on Plan Assets Still Held			7
Purchases, Sales, and Settlements			(7)
Assets Transferred into (out of) Level 3			0
Predecessor [Member] | Derivative, Asset [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			0					0
Actual Return (Loss) on Plan Assets Sold			0
Actual Return (Loss) on Plan Assets Still Held			0
Purchases, Sales, and Settlements			0
Assets Transferred into (out of) Level 3			0
Successor [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,284	[1]	20,395	[1]	18,918
Successor [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	161				330		$ 181
Actual Return (Loss) on Plan Assets Sold	(3)				(83)
Actual Return (Loss) on Plan Assets Still Held	6				72
Purchases, Sales, and Settlements	(23)				202
Assets Transferred into (out of) Level 3					(22)
Successor [Member] | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27				14		46
Actual Return (Loss) on Plan Assets Sold	(3)				(80)
Actual Return (Loss) on Plan Assets Still Held	5				87
Purchases, Sales, and Settlements	(21)				(15)
Assets Transferred into (out of) Level 3					(5)
Successor [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2				0		2
Actual Return (Loss) on Plan Assets Sold	0				0
Actual Return (Loss) on Plan Assets Still Held	0				0
Purchases, Sales, and Settlements	0				0
Assets Transferred into (out of) Level 3					(2)
Successor [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2				0		0
Actual Return (Loss) on Plan Assets Sold	0				0
Actual Return (Loss) on Plan Assets Still Held	0				0
Purchases, Sales, and Settlements	2				0
Assets Transferred into (out of) Level 3					(2)
Successor [Member] | Private Market Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14				1		17
Actual Return (Loss) on Plan Assets Sold	0				0
Actual Return (Loss) on Plan Assets Still Held	(3)				(3)
Purchases, Sales, and Settlements	0				0
Assets Transferred into (out of) Level 3					(10)
Successor [Member] | Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	96				93		98
Actual Return (Loss) on Plan Assets Sold	0				2
Actual Return (Loss) on Plan Assets Still Held	4				0
Purchases, Sales, and Settlements	(6)				(3)
Assets Transferred into (out of) Level 3					(2)
Successor [Member] | Derivative, Asset [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0				206		0
Actual Return (Loss) on Plan Assets Sold	0				0
Actual Return (Loss) on Plan Assets Still Held	0				(11)
Purchases, Sales, and Settlements	0				217
Assets Transferred into (out of) Level 3					0
UNITED STATES | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,043	[2]			3,537	[3]
UNITED STATES | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17				14
UNITED STATES | Predecessor [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			16					18
Actual Return (Loss) on Plan Assets Sold			(1)
Actual Return (Loss) on Plan Assets Still Held			(7)
Purchases, Sales, and Settlements			6
Assets Transferred into (out of) Level 3			0
UNITED STATES | Successor [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17				14		16
Actual Return (Loss) on Plan Assets Sold	0				(1)
Actual Return (Loss) on Plan Assets Still Held	1				(4)
Purchases, Sales, and Settlements	0				3
Assets Transferred into (out of) Level 3					(1)
Non-US [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,064				2,582
Non-US [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3				2
Non-US [Member] | Predecessor [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			2					$ 1
Actual Return (Loss) on Plan Assets Sold			2
Actual Return (Loss) on Plan Assets Still Held			(2)
Purchases, Sales, and Settlements			1
Assets Transferred into (out of) Level 3			$ 0
Non-US [Member] | Successor [Member] | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3				2		$ 2
Actual Return (Loss) on Plan Assets Sold	0				(4)
Actual Return (Loss) on Plan Assets Still Held	(1)				3
Purchases, Sales, and Settlements	$ 2				0
Assets Transferred into (out of) Level 3					$ 0

[1] The benefit obligation and the fair value of plan assets at the beginning of the period September 1 through December 31, 2017, reflects the remeasurement of the plans at the Merger Effectiveness Time.

[2] The Historical DuPont pension plans directly held $910 million (4 percent of total plan assets) of DowDuPont common stock at December 31, 2017.

[3] The Historical DuPont pension plans directly held $684 million (4 percent of total plan assets) of DowDuPont common stock at December 31, 2018.