Long-Duration Insurance Contracts - Reconciliation of LFPB to Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	$ 1,624.4	$ 1,622.8
Whole life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	279.5	275.2
Term life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	141.0	131.8
Experience life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	743.1	746.6
Limited-Pay Whole Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	54.6	52.1
Supplemental health
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	198.5	203.5
SPIA (life contingent)
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	97.1	97.3
Limited-pay whole life DPL
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	5.5	5.2
SPIA (life contingent) DPL
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	1.5	1.5
Reconciling items
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	$ 103.7	$ 109.6