Long-Duration Insurance Contracts - Reconciliation of LFPB to Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	$ 1,579.3	$ 1,611.5
Whole life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	274.4	278.8
Term life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	143.2	144.1
Experience life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	721.3	740.8
Limited-Pay Whole Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	54.1	54.6
Supplemental health
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	188.0	191.8
SPIA (life contingent)
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	93.2	96.0
Limited-pay whole life DPL
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	6.5	6.2
SPIA (life contingent) DPL
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	1.4	1.5
Reconciling items
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net liability for future policy benefits	$ 97.2	$ 97.7