Derivatives - Classification and Fair Value of Derivatives in Consolidated Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivatives
Derivative assets	$ 11.4	$ 4.1
Derivative liabilities	9.5	5.1
Interest rate cap \| Derivatives not designated as hedging instruments
Derivatives
Notional Value	250.0	250.0
Interest rate cap \| Derivatives not designated as hedging instruments \| Other assets
Derivatives
Derivative assets	0.0	0.2
Interest rate cap \| Derivatives not designated as hedging instruments \| Other liabilities
Derivatives
Derivative liabilities	0.0	0.0
Foreign currency swaps \| Derivatives not designated as hedging instruments
Derivatives
Notional Value	90.0	45.0
Foreign currency swaps \| Derivatives not designated as hedging instruments \| Other assets
Derivatives
Derivative assets	0.0	0.0
Foreign currency swaps \| Derivatives not designated as hedging instruments \| Other liabilities
Derivatives
Derivative liabilities	3.6	4.6
Foreign currency forwards \| Derivatives not designated as hedging instruments
Derivatives
Notional Value	30.0	0.0
Foreign currency forwards \| Derivatives not designated as hedging instruments \| Other assets
Derivatives
Derivative assets	2.7	0.0
Foreign currency forwards \| Derivatives not designated as hedging instruments \| Other liabilities
Derivatives
Derivative liabilities	5.7	0.0
Weather derivatives \| Derivatives not designated as hedging instruments
Derivatives
Notional Value	110.7	150.5
Weather derivatives \| Derivatives not designated as hedging instruments \| Other assets
Derivatives
Derivative assets	7.0	3.9
Weather derivatives \| Derivatives not designated as hedging instruments \| Other liabilities
Derivatives
Derivative liabilities	0.0	0.0
Equity futures contracts \| Derivatives not designated as hedging instruments
Derivatives
Notional Value	34.5	0.0
Equity futures contracts \| Derivatives not designated as hedging instruments \| Other assets
Derivatives
Derivative assets	0.0	0.0
Equity futures contracts \| Derivatives not designated as hedging instruments \| Other liabilities
Derivatives
Derivative liabilities	0.0	0.0
Equity warrants \| Derivatives not designated as hedging instruments
Derivatives
Notional Value	0.4	0.0
Equity warrants \| Derivatives not designated as hedging instruments \| Other assets
Derivatives
Derivative assets	0.4	0.0
Equity warrants \| Derivatives not designated as hedging instruments \| Other liabilities
Derivatives
Derivative liabilities	0.0	0.0
Equity put options \| Derivatives not designated as hedging instruments
Derivatives
Notional Value	31.0	6.2
Equity put options \| Derivatives not designated as hedging instruments \| Other assets
Derivatives
Derivative assets	1.3	0.0
Equity put options \| Derivatives not designated as hedging instruments \| Other liabilities
Derivatives
Derivative liabilities	$ 0.2	$ 0.5

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Nominal or face amount used to calculate payment on derivative.

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