Segment Reporting Segment Information (Details) - USD ($) $ in Millions		3 Months Ended									12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019		Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018	Jun. 01, 2019
Segment Reporting Information [Line Items]
Net Sales		$ 3,207	$ 1,863	$ 5,191	$ 3,956	$ 2,983		$ 1,911	$ 5,556	$ 3,396	$ 14,217	$ 13,846		$ 14,287
Segment Operating EBITDA	[1]										2,212	2,106		2,213
Depreciation and Amortization												1,599		2,790
Segment Assets		36,850				38,879	[2]				36,850	38,879	[2]	38,632
Investments in nonconsolidated affiliates		66				66					66	66
Payments to Acquire Property, Plant, and Equipment												1,163		1,501
Goodwill		10,269				10,229					10,269	10,229		10,193	$ 10,179
Reallocation of goodwill [Member]
Segment Reporting Information [Line Items]
Goodwill															3,382
Operating Segments [Member]
Segment Reporting Information [Line Items]
Depreciation and Amortization											1,177	1,000		909
Investments in nonconsolidated affiliates		66				66					66	66		138
Payments to Acquire Property, Plant, and Equipment											475	666		513
Seed [Member]
Segment Reporting Information [Line Items]
Net Sales											7,756	7,590		7,842
Segment Operating EBITDA											1,208	1,040		1,139
Depreciation and Amortization											798	628		534
Segment Assets		23,751				25,387	[2]				23,751	25,387	[2]	29,286
Investments in nonconsolidated affiliates		22				27					22	27		102
Payments to Acquire Property, Plant, and Equipment											225	373		263
Goodwill		5,524				5,486					5,524	5,486		0	5,453
Crop Protection [Member]
Segment Reporting Information [Line Items]
Net Sales											6,461	6,256		6,445
Segment Operating EBITDA											1,004	1,066		1,074
Depreciation and Amortization											379	372		375
Segment Assets		13,099				13,492	[2]				13,099	13,492	[2]	9,346
Investments in nonconsolidated affiliates		44				39					44	39		36
Payments to Acquire Property, Plant, and Equipment											250	293		250
Goodwill		$ 4,745				$ 4,743					$ 4,745	$ 4,743		$ 0	$ 4,726

[1] The years ended December 31, 2019 and December 31, 2018 are presented on a pro forma basis, prepared in accordance with Article 11 of Regulation S-X that was in effect prior to recent amendments.

[2] 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.