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	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 16,941		$ 18,951		$ 20,329
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52		330	[1]	161
Actual Return (Loss) on Plan Assets Sold	(21)		(83)
Actual Return (Loss) on Plan Assets Still Held	16		72
Purchases, Sales, and Settlements	(14)		202
Assets Transferred into (out of) Level 3	0		(22)
Plan assets transferred due to sale, liquidation, spin-off, or divestiture	(259)
Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,956		3,037
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4		14		27
Actual Return (Loss) on Plan Assets Sold	9		(80)
Actual Return (Loss) on Plan Assets Still Held	(8)		87
Purchases, Sales, and Settlements	(12)		(15)
Assets Transferred into (out of) Level 3	1		(5)
Plan assets transferred due to sale, liquidation, spin-off, or divestiture	0
Asset-backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	663		721
Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0		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	0		(2)
Plan assets transferred due to sale, liquidation, spin-off, or divestiture	0
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			162
Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0		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	0		(2)
Plan assets transferred due to sale, liquidation, spin-off, or divestiture	0
Private Market Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2		1
Private Market Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2		1		14
Actual Return (Loss) on Plan Assets Sold	0		0
Actual Return (Loss) on Plan Assets Still Held	4		(3)
Purchases, Sales, and Settlements	(3)		0
Assets Transferred into (out of) Level 3	0		(10)
Plan assets transferred due to sale, liquidation, spin-off, or divestiture	0
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	33		336
Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	33		93		96
Actual Return (Loss) on Plan Assets Sold	(29)		2
Actual Return (Loss) on Plan Assets Still Held	25		0
Purchases, Sales, and Settlements	(3)		(3)
Assets Transferred into (out of) Level 3	0		(2)
Plan assets transferred due to sale, liquidation, spin-off, or divestiture	(53)
Derivative, Asset [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19		233
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		0
Plan assets transferred due to sale, liquidation, spin-off, or divestiture	(206)
Non-US [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,053		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	4		2		3
Actual Return (Loss) on Plan Assets Sold	1		(4)
Actual Return (Loss) on Plan Assets Still Held	0		3
Purchases, Sales, and Settlements	2		0
Assets Transferred into (out of) Level 3	(1)		0
Plan assets transferred due to sale, liquidation, spin-off, or divestiture	0
UNITED STATES | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,665	[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	9		14		$ 17
Actual Return (Loss) on Plan Assets Sold	(2)		(1)
Actual Return (Loss) on Plan Assets Still Held	(5)		(4)
Purchases, Sales, and Settlements	2		3
Assets Transferred into (out of) Level 3	0		$ (1)
Plan assets transferred due to sale, liquidation, spin-off, or divestiture	$ 0

[1] Corteva's pension assets by fair value hierarchy at December 31, 2018 included approximately $1,657 million of Level 1 assets, $392 million of Level 2 assets, $259 million of Level 3 assets, and $606 million of investments measured at net asset value that were transferred to DuPont upon completion of the Separation.

[2] The Corteva pension plans directly held $126 million (approximately 1 percent of total plan assets) of Corteva, Inc. common stock at December 31, 2019.

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