v3.26.1
FAIR VALUE MEASUREMENTS - FAIR VALUE INPUTS (Details)
$ in Millions
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Jun. 30, 2025
USD ($)
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Equity securities - corporate securities $ 337.2 $ 389.2  
Market risk benefit liability 50.6 48.1 $ 63.8
Embedded derivatives related to fixed indexed annuity products 1,676.7 1,600.6  
Total liabilities carried at fair value 1,727.3 1,648.7  
Corporate securities      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Equity securities - corporate securities 319.6 367.2  
Significant unobservable inputs  (Level 3)      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Total assets carried at fair value by category 75.1 76.1  
Market risk benefit liability 50.6 48.1  
Embedded derivatives related to fixed indexed annuity products 1,676.7 1,600.6  
Total liabilities carried at fair value 1,727.3 $ 1,648.7  
Significant unobservable inputs  (Level 3) | Recovery method | Percent of recovery expected | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, fixed maturities   0.5000  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Market risk benefit liability $ 50.6 $ 48.1  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Surrender rates | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0046 0.0046  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Surrender rates | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.1768 0.1768  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Surrender rates | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0344 0.0344  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Partial withdrawal rates | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0000 0.0000  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Partial withdrawal rates | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0300 0.0300  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Partial withdrawal rates | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0096 0.0096  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Mortality | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0003 0.0003  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Mortality | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.3975 0.3975  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Mortality | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0363 0.0363  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | GLWB utilization | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0592 0.0592  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | GLWB utilization | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.4762 0.4762  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | GLWB utilization | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.2507 0.2507  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Non-performance risk spread | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0008 0.0009  
Significant unobservable inputs  (Level 3) | Discounted cash flow analysis | Non-performance risk spread | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, market risk benefit, liability measurement input 0.0031 0.0031  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Embedded derivatives related to fixed indexed annuity products $ 1,676.7 $ 1,600.6  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Surrender rates | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0046 0.0046  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Surrender rates | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.2336 0.2336  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Surrender rates | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0611 0.0611  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Partial withdrawal rates | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0000 0.0000  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Partial withdrawal rates | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0450 0.0450  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Partial withdrawal rates | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0278 0.0278  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Mortality | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0003 0.0003  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Mortality | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.3975 0.3975  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Mortality | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0405 0.0405  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | GLWB utilization | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0592 0.0592  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | GLWB utilization | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.4762 0.4762  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | GLWB utilization | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.2507 0.2507  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Non-performance risk spread | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0008 0.0009  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Non-performance risk spread | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0031 0.0031  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Option budget | Minimum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0090 0.0090  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Option budget | Maximum      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0338 0.0338  
Significant unobservable inputs  (Level 3) | Discounted projected embedded derivatives | Option budget | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, liabilities 0.0264 0.0264  
Significant unobservable inputs  (Level 3) | Corporate securities      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Equity securities - corporate securities $ 73.5 $ 73.7  
Significant unobservable inputs  (Level 3) | Corporate securities | Recovery method      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Fixed maturities, available for sale $ 0.3 0.5  
Significant unobservable inputs  (Level 3) | Corporate securities | Recovery method | Percent of recovery expected      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, fixed maturities 0.2500    
Significant unobservable inputs  (Level 3) | Asset-backed securities | Recovery method      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Fixed maturities, available for sale $ 3.4 $ 3.5  
Significant unobservable inputs  (Level 3) | Asset-backed securities | Recovery method | Percent of recovery expected | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, equity securities 0.6032 0.6124  
Significant unobservable inputs  (Level 3) | Asset-backed securities | Discounted cash flow analysis      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Fixed maturities, available for sale $ 7.1 $ 7.6  
Significant unobservable inputs  (Level 3) | Asset-backed securities | Discounted cash flow analysis | Discount margins | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, fixed maturities 0.0160 0.0161  
Significant unobservable inputs  (Level 3) | Equity Securities | Market comparables      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Equity securities - corporate securities $ 64.3 $ 64.5  
Significant unobservable inputs  (Level 3) | Equity Securities | Market comparables | EBITDA multiples | Weighted Average      
Fair Value, Assets on Recurring Basis, Unobservable Input Reconciliation [Line Items]      
Unobservable inputs, equity securities 11.6 10.9