Acquisitions (Asset Acquisition) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Research and Development Assets Acquired Other than Through Business Combination [Line Items]
Research and Development Asset Acquired Other than Through Business Combination, Written-off	$ (4.1)	$ 1,183.0	$ 0.0

The amount of the write-off for research and development assets that were acquired in a transaction other than a business combination.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

Name:	us-gaap_ResearchAndDevelopmentAssetAcquiredOtherThanThroughBusinessCombinationWrittenOff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration