Segment Reporting Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								9 Months Ended
	Sep. 30, 2020		Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019		Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020		Sep. 30, 2019		Dec. 31, 2019
Segment Reporting Information [Line Items]
Net Sales	$ 1,863				$ 1,911				$ 11,010		$ 10,863
Segment operating EBITDA	(152)				(176)				1,932		1,855	[1]
Segment Assets	36,965				39,352				36,965		39,352		$ 38,879
Share-based compensation	15		$ 19	$ 2	12		$ 55	$ 18
Additional Paid-in Capital [Member]
Segment Reporting Information [Line Items]
Share-based compensation	16		$ 19	$ 2	12		$ 11
Seed [Member]
Segment Reporting Information [Line Items]
Net Sales	523				681				6,516		6,347
Segment operating EBITDA	(282)				(295)				1,255		1,066
Segment Assets	24,372	[2]			26,021	[2]			24,372	[2]	26,021	[2]	25,387
Crop Protection [Member]
Segment Reporting Information [Line Items]
Net Sales	1,340				1,230				4,494		4,516
Segment operating EBITDA	130				119				677		789
Segment Assets	$ 12,593	[2]			$ 13,331	[2]			$ 12,593	[2]	$ 13,331	[2]	$ 13,492

[1] The nine months ended September 30, 2019 is presented on a pro forma basis, prepared in accordance with Article 11 of Regulation S-X.

[2] Segment assets at December 31, 2019 were $25,387 million and $13,492 million for Seed and Crop Protection, respectively.