Segment Reporting Segment Assets (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Segment Reporting Information [Line Items]
Segment Assets		$ 36,850	$ 38,879	[1]	$ 38,632
Corporate Assets		5,799	3,518		4,417
Assets		$ 42,649	$ 42,397		108,683
Assets of discontinued operations - current [Member]
Segment Reporting Information [Line Items]
Assets	[2]				$ 65,634

[1] 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.

[2] See Note 5 - Divestitures and Other Transactions, to the Consolidated Financial Statements, for additional information on discontinued operations.