Segment Reporting Segment Information (Details) - USD ($) $ in Millions		3 Months Ended									4 Months Ended	8 Months Ended	12 Months Ended
		Dec. 31, 2019		Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2019		Dec. 31, 2018	Jun. 01, 2019
Segment Reporting Information [Line Items]
Net Sales		$ 2,983		$ 1,911	$ 5,556	$ 3,396	$ 2,815	$ 1,947	$ 5,731	$ 3,794	$ 3,790	$ 6,894	$ 13,846		$ 14,287
Pro forma Segment Operating EBITDA	[1]												2,106		2,213
Depreciation and Amortization													1,599		2,790
Segment Assets		38,879					38,632						38,879		38,632
Investments in nonconsolidated affiliates		66					138						66		138
Payments to Acquire Property, Plant, and Equipment													1,163		1,501
Goodwill		10,229					10,193				14,873		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													1,000		909
Segment Assets		38,879					38,632						38,879		38,632
Investments in nonconsolidated affiliates		66					138						66		138
Payments to Acquire Property, Plant, and Equipment													666		513
Seed [Member]
Segment Reporting Information [Line Items]
Net Sales											1,520	5,865	7,590		7,842
Pro forma Segment Operating EBITDA													1,040		1,139
Depreciation and Amortization													628		534
Segment Assets		25,387	[2]				29,286						25,387	[2]	29,286
Investments in nonconsolidated affiliates		27					102						27		102
Payments to Acquire Property, Plant, and Equipment													373		263
Goodwill		5,486					0				0		5,486		0	5,453
Crop Protection [Member]
Segment Reporting Information [Line Items]
Net Sales											2,270	$ 1,029	6,256		6,445
Pro forma Segment Operating EBITDA													1,066		1,074
Depreciation and Amortization													372		375
Segment Assets		13,492	[2]				9,346						13,492	[2]	9,346
Investments in nonconsolidated affiliates		39					36						39		36
Payments to Acquire Property, Plant, and Equipment													293		250
Goodwill		$ 4,743					$ 0				$ 0		$ 4,743		$ 0	$ 4,726

[1] Segment operating EBITDA for all periods is presented on a pro forma basis, prepared in accordance with Article 11 of Regulation S-X.

[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.