Investments - Schedule of Unrealized Losses for Fixed Maturities and Equity Securities (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Fixed Maturity Securities, Unrealized Losses
Less than 20%	$ (58.0)	$ (32.6)
20% or more for less than six months	(252.2)	0.0
20% or more for six months or greater	(2.0)	(0.8)
Total	$ (312.2)	$ (33.4)
Fixed Maturity Securiites, Percentage of Sales
Less than 20%	18.60%	97.60%
20% or more for less than six months	80.80%	0.00%
20% or more for six months or greater	0.60%	2.40%
Total	100.00%	100.00%