Income Taxes - Net Operating Losses Carryforwards (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Federal [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 1,572.9	$ 1,519.9
State [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	1,090.7	1,068.3
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 229.4	$ 306.8

Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32559-109319

Name:	us-gaap_OperatingLossCarryforwards
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant