Goodwill and Intangible Assets - Finite-lived Intangible Assets (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	$ 147.7	$ 383.8	$ 354.6
Policies in force
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	0.0	256.2	256.2
Accumulated Amortization	0.0	247.1	228.7
Net Carrying Amount	0.0	9.1	27.5
Agency relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	159.2	159.2	159.2
Accumulated Amortization	82.5	76.8	71.1
Net Carrying Amount	76.7	82.4	88.1
Software rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	69.1	69.1	69.1
Accumulated Amortization	62.6	58.3	54.0
Net Carrying Amount	6.5	10.8	15.1
Trade name
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3.6	3.6	3.6
Accumulated Amortization	2.0	1.0	0.2
Net Carrying Amount	1.6	2.6	3.4
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	231.9	488.1	488.1
Accumulated Amortization	147.1	383.2	354.0
Net Carrying Amount	$ 84.8	$ 104.9	$ 134.1