Segment Reporting Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020		Mar. 31, 2019		Dec. 31, 2019	Jun. 01, 2019
Segment Reporting Information [Line Items]
Net Sales	$ 3,956		$ 3,396
Segment operating EBITDA	819		545	[1]
Segment Assets	39,108		40,041		$ 38,879
Goodwill	10,027		10,203		10,229
Seed [Member]
Segment Reporting Information [Line Items]
Net Sales	2,455		1,967
Segment operating EBITDA	581		325
Segment Assets	25,857	[2],[3]	30,259	[2],[3]	25,387
Crop Protection [Member]
Segment Reporting Information [Line Items]
Net Sales	1,501		1,429
Segment operating EBITDA	238		220
Segment Assets	$ 13,251	[2],[3]	$ 9,782	[2],[3]	$ 13,492
Reallocation of goodwill [Member]
Segment Reporting Information [Line Items]
Goodwill						$ 3,382

[1] Period 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.

[3] On June 1, 2019, as a result of changes in reportable segments, $3,382 million of goodwill was reallocated from the Seed reportable segment to the Crop Protection reportable segment.  This change was not reflected in segment assets prior to June 1, 2019.