v3.25.2
Fair Value Measurements - Quantitative Information for Level 3 Measurements (Details) - Recurring Fair Value Measurements
$ in Millions
Jun. 30, 2025
USD ($)
Dec. 31, 2024
USD ($)
Unobservable inputs    
Assets measured at fair value $ 258,274.1 $ 249,740.8
Liabilities measured at fair value 1,311.1 1,840.8
Fair value hierarchy Level 3    
Unobservable inputs    
Assets measured at fair value 5,866.2 5,680.2
Liabilities measured at fair value 1,874.0 2,366.1
Fair value hierarchy Level 3 | Investment and universal life contracts    
Unobservable inputs    
Liabilities measured at fair value $ (863.7) $ (578.4)
Embedded derivative, Valuation technique Discounted cash flow Discounted cash flow
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long duration interest rate | Minimum    
Unobservable inputs    
Embedded derivative, Input 0.034 0.03
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long duration interest rate | Maximum    
Unobservable inputs    
Embedded derivative, Input 0.048 0.049
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long duration interest rate | Weighted average input    
Unobservable inputs    
Embedded derivative, Input 0.047 0.048
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long-term equity market volatility | Minimum    
Unobservable inputs    
Embedded derivative, Input 0.164 0.145
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long-term equity market volatility | Maximum    
Unobservable inputs    
Embedded derivative, Input 0.257 0.493
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Long-term equity market volatility | Weighted average input    
Unobservable inputs    
Embedded derivative, Input 0.199 0.214
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Non-performance risk | Minimum    
Unobservable inputs    
Embedded derivative, Input 0.005 0.004
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Non-performance risk | Maximum    
Unobservable inputs    
Embedded derivative, Input 0.012 0.011
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Non-performance risk | Weighted average input    
Unobservable inputs    
Embedded derivative, Input 0.01 0.008
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Lapse rate | Minimum    
Unobservable inputs    
Embedded derivative, Input 0 0
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Lapse rate | Maximum    
Unobservable inputs    
Embedded derivative, Input 0.55 0.55
Fair value hierarchy Level 3 | Investment and universal life contracts | Discounted cash flow | Lapse rate | Weighted average input    
Unobservable inputs    
Embedded derivative, Input 0.08 0.085
Fair value hierarchy Level 3 | Fixed maturities | Trading    
Unobservable inputs    
Assets measured at fair value $ 300.8 $ 289.6
Fixed maturities, trading, Valuation technique Discounted cash flow Discounted cash flow
Fair value hierarchy Level 3 | Fixed maturities | Trading | Discounted cash flow | Discount rate | Minimum    
Unobservable inputs    
Fixed maturities, trading, Input 0.094 0.095
Fair value hierarchy Level 3 | Fixed maturities | Trading | Discounted cash flow | Discount rate | Maximum    
Unobservable inputs    
Fixed maturities, trading, Input 0.13 0.13
Fair value hierarchy Level 3 | Fixed maturities | Trading | Discounted cash flow | Discount rate | Weighted average input    
Unobservable inputs    
Fixed maturities, trading, Input 0.097 0.099
Fair value hierarchy Level 3 | Fixed maturities | Trading | Discounted cash flow | Earnings before interest, taxes, depreciation and amortization multiple    
Unobservable inputs    
Fixed maturities, trading, Input 1.1 1.1
Fair value hierarchy Level 3 | Fixed maturities | Trading | Discounted cash flow | Earnings before interest, taxes, depreciation and amortization multiple | Weighted average input    
Unobservable inputs    
Fixed maturities, trading, Input 1.1 1.1
Fair value hierarchy Level 3 | Fixed maturities | Trading | Discounted cash flow | Comparability adjustment | Minimum    
Unobservable inputs    
Fixed maturities, trading, Input (0.0041) (0.0032)
Fair value hierarchy Level 3 | Fixed maturities | Trading | Discounted cash flow | Comparability adjustment | Maximum    
Unobservable inputs    
Fixed maturities, trading, Input 0.0697 0.2947
Fair value hierarchy Level 3 | Fixed maturities | Trading | Discounted cash flow | Comparability adjustment | Weighted average input    
Unobservable inputs    
Fixed maturities, trading, Input 0.0101 0.0152
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale    
Unobservable inputs    
Assets measured at fair value $ 2,055.5 $ 1,817.8
Fixed maturities, available-for-sale, Valuation technique Discounted cash flow Discounted cash flow
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Discount rate | Minimum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.029 0.021
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Discount rate | Maximum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.124 0.127
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Discount rate | Weighted average input    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.08 0.08
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Earnings before interest, taxes, depreciation and amortization multiple    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 1.1  
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Earnings before interest, taxes, depreciation and amortization multiple | Minimum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input   1.1
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Earnings before interest, taxes, depreciation and amortization multiple | Maximum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input   1.7
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Earnings before interest, taxes, depreciation and amortization multiple | Weighted average input    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 1.1 1.3
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Illiquidity premium | Minimum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.0030 0.0030
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Illiquidity premium | Maximum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.0771 0.0791
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Illiquidity premium | Weighted average input    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.0146 0.0142
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Comparability adjustment | Minimum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input (0.0050) (0.0042)
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Comparability adjustment | Maximum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.1984 0.2947
Fair value hierarchy Level 3 | Corporate debt securities | Available-for-sale | Discounted cash flow | Comparability adjustment | Weighted average input    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.0111 0.0149
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale    
Unobservable inputs    
Assets measured at fair value $ 1,723.9 $ 1,343.1
Fixed maturities, available-for-sale, Valuation technique Discounted cash flow Discounted cash flow
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Discount rate | Minimum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.034 0.049
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Discount rate | Maximum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.08 0.077
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Discount rate | Weighted average input    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.044 0.054
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Illiquidity premium | Minimum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input (0.0083) (0.0083)
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Illiquidity premium | Maximum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.0415 0.0260
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Illiquidity premium | Weighted average input    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.0173 0.0120
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Comparability adjustment | Minimum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input (0.0018) (0.0019)
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Comparability adjustment | Maximum    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.0319 0.0415
Fair value hierarchy Level 3 | Other debt obligations | Available-for-sale | Discounted cash flow | Comparability adjustment | Weighted average input    
Unobservable inputs    
Fixed maturities, available-for-sale, Input 0.0072 0.0128
Fair value hierarchy Level 3 | Other investments    
Unobservable inputs    
Assets measured at fair value $ 114.1 $ 129.0
Fair value hierarchy Level 3 | Other investments | Discounted cash flow | Discount rate | Minimum    
Unobservable inputs    
Other investments, Input 0.115 0.115
Fair value hierarchy Level 3 | Other investments | Discounted cash flow | Discount rate | Maximum    
Unobservable inputs    
Other investments, Input 0.135 0.135
Fair value hierarchy Level 3 | Other investments | Discounted cash flow | Discount rate | Weighted average input    
Unobservable inputs    
Other investments, Input 0.122 0.124
Fair value hierarchy Level 3 | Other investments | Discounted cash flow | Probability of default | Minimum    
Unobservable inputs    
Other investments, Input 0.06 0.06
Fair value hierarchy Level 3 | Other investments | Discounted cash flow | Probability of default | Maximum    
Unobservable inputs    
Other investments, Input 0.10 0.10
Fair value hierarchy Level 3 | Other investments | Discounted cash flow | Probability of default | Weighted average input    
Unobservable inputs    
Other investments, Input 0.077 0.081
Fair value hierarchy Level 3 | Other investments | Discounted cash flow | Potential loss severity | Minimum    
Unobservable inputs    
Other investments, Input 0.88 0.87
Fair value hierarchy Level 3 | Other investments | Discounted cash flow | Potential loss severity | Maximum    
Unobservable inputs    
Other investments, Input 1 1
Fair value hierarchy Level 3 | Other investments | Discounted cash flow | Potential loss severity | Weighted average input    
Unobservable inputs    
Other investments, Input 0.936 0.92
Fair value hierarchy Level 3 | Separate account assets    
Unobservable inputs    
Assets measured at fair value $ 741.4 $ 726.7
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Discount rate | Minimum    
Unobservable inputs    
Separate account assets, Input 0.07 0.07
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Discount rate | Maximum    
Unobservable inputs    
Separate account assets, Input 0.105 0.11
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Discount rate | Weighted average input    
Unobservable inputs    
Separate account assets, Input 0.072 0.072
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Terminal capitalization rate | Minimum    
Unobservable inputs    
Separate account assets, Input 0.055 0.055
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Terminal capitalization rate | Maximum    
Unobservable inputs    
Separate account assets, Input 0.095 0.095
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Terminal capitalization rate | Weighted average input    
Unobservable inputs    
Separate account assets, Input 0.06 0.06
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Average market rent growth rate | Minimum    
Unobservable inputs    
Separate account assets, Input 0.018 0.02
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Average market rent growth rate | Maximum    
Unobservable inputs    
Separate account assets, Input 0.059 0.045
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate | Average market rent growth rate | Weighted average input    
Unobservable inputs    
Separate account assets, Input 0.028 0.027
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Loan to value | Minimum    
Unobservable inputs    
Separate account assets, Input 0.464 0.464
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Loan to value | Maximum    
Unobservable inputs    
Separate account assets, Input 0.695 0.695
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Loan to value | Weighted average input    
Unobservable inputs    
Separate account assets, Input 0.575 0.592
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Market interest rate | Minimum    
Unobservable inputs    
Separate account assets, Input 0.051 0.049
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Market interest rate | Maximum    
Unobservable inputs    
Separate account assets, Input 0.068 0.072
Fair value hierarchy Level 3 | Separate account assets | Discounted cash flow, real estate debt | Market interest rate | Weighted average input    
Unobservable inputs    
Separate account assets, Input 0.057 0.061