Discontinued Operations (Summary of Revenue and Net Income from Discontinued Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue from discontinued operations	$ 24,539.8	$ 22,319.5	$ 21,493.3
Net income from discontinued operations	$ 0.0	3,680.5	81.4
Elanco | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue from discontinued operations		580.0	3,062.4
Net income from discontinued operations		$ 3,680.5	$ 81.4