Investments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Schedule of Investments [Line Items]
Impairment losses on investments	$ 0.2	$ (1.4)	$ 0.2	$ 27.1
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Impairment losses on investments	0.2	$ 1.4	0.2	20.8
Impairments on fixed maturities included intend to sell				16.2
Impairments on fixed maturities credit related losses				4.6
Mortgage Loans [Member]
Schedule of Investments [Line Items]
Impairment losses on investments				$ 4.8
Allowance for credit losses	7.9		7.9		$ 7.9
Fixed Maturities Including Held For Sale [Member]
Schedule of Investments [Line Items]
Allowance for credit losses	$ 0.1		$ 0.1		$ 0.1