Income Taxes Expected Expirations of Federal and State Losses and Credits (Details) $ in Millions	Dec. 31, 2020 USD ($)
Federal
Expirations of Operating Loss Carryforwards, Components [Abstract]
2021	$ 2.3
2022	6.1
2023	5.3
2024	14.5
2025 and thereafter	267.7
Indefinite	270.3
Total	566.2
State
Expirations of Operating Loss Carryforwards, Components [Abstract]
2021	0.3
2022	0.4
2023	1.2
2024	9.1
2025 and thereafter	132.9
Indefinite	0.0
Total	143.9
Research Tax Credit Carryforward \| Federal
Expirations of Tax Credit Carryforwards [Abstract]
2021	0.0
2022	0.0
2023	0.0
2024	0.0
2025 and thereafter	19.8
Indefinite	0.0
Total	19.8
Research Tax Credit Carryforward \| State
Expirations of Tax Credit Carryforwards [Abstract]
2021	0.0
2022	0.0
2023	0.0
2024	0.0
2025 and thereafter	0.0
Indefinite	3.2
Total	$ 3.2

Operating Loss Carryforwards, Expiring in Five Years

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

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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)
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The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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