Investment Securities (Cost and Amortized Cost Maturity Schedule) (Details) $ in Millions	Dec. 31, 2019 USD ($)
Trading Securities by Maturity Cost or Amortized Cost
Cost of Amortized Cost	$ 1,177.9
Trading Securities by Maturity, Fair Value
Carrying Value of Fixed Maturities	1,205.8
Fixed Maturities and Convertible Fixed Maturities Excluding A B S M B S and Preferred Stock
Trading Securities by Maturity Cost or Amortized Cost
Due in one year or less	190.0
Due after one year through five years	481.6
Due after five years through ten years	165.3
Due after ten years	134.4
Trading Securities by Maturity, Fair Value
Due in one year or less	190.8
Due after one year through five years	489.3
Due after five years through ten years	173.2
Due after ten years	143.5
Mortgage and asset-backed securities
Trading Securities by Maturity Cost or Amortized Cost
Mortgage and asset-backed securities	206.6
Trading Securities by Maturity, Fair Value
Mortgage and asset-backed securities	$ 209.0

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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This item represents the carrying value of debt securities which are expected to mature after five years and through ten years from the balance sheet date classified as trading.

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