v3.26.1
Fair Value Measurements - Significant Unobservable Inputs Securities (Details)
$ in Millions
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale $ 45,824 $ 46,041
Other Short-term Investments 3,866 4,004
Equity Securities, FV-NI 560 422
Assets, Fair Value Disclosure 50,372 50,655
ABS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 4,783 4,663
Collateralized Loan Obligations [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 3,360 3,316
CMBS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 1,822 2,328
Corporate    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 23,868 23,076
RMBS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 5,787 6,178
Significant
Unobservable
Inputs
(Level 3)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 3,403 3,372
Other Short-term Investments 709 382
Equity Securities, FV-NI 124 106
Assets, Fair Value Disclosure 4,361 4,028
Significant
Unobservable
Inputs
(Level 3) | ABS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 175 167
Significant
Unobservable
Inputs
(Level 3) | Collateralized Loan Obligations [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 200 217
Significant
Unobservable
Inputs
(Level 3) | CMBS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 97 115
Significant
Unobservable
Inputs
(Level 3) | Corporate    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 2,916 2,866
Significant
Unobservable
Inputs
(Level 3) | RMBS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 15 7
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | ABS | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale $ 175 $ 167
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | ABS | Minimum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 4.88 4.34
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | ABS | Maximum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 9.02 8.43
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | ABS | Weighted Average [Member] | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 5.90 5.30
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Collateralized Loan Obligations [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale $ 200 $ 217
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Collateralized Loan Obligations [Member] | Minimum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 2.79 2.70
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Collateralized Loan Obligations [Member] | Maximum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 10.07 10.21
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Collateralized Loan Obligations [Member] | Weighted Average [Member] | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 5.51 5.44
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | CMBS | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale $ 96 $ 115
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | CMBS | Minimum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 2.70 2.45
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | CMBS | Maximum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 12.70 10
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | CMBS | Weighted Average [Member] | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 4.35 3.97
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Corporate | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale $ 2,796 $ 2,765
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Corporate | Minimum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.97 0.88
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Corporate | Maximum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 10.41 8.11
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Corporate | Weighted Average [Member] | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 2.83 2.89
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale $ 15 $ 7
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Minimum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.88 0.88
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Minimum | Measurement Input, Constant Prepayment Rate [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.02 0.02
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Minimum | Measurement Input, Default Rate [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.01 0.01
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Minimum | Measurement Input, Loss Severity [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.35 0.37
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Maximum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 1.84 5.51
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Maximum | Measurement Input, Constant Prepayment Rate [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.05 0.05
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Maximum | Measurement Input, Default Rate [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.05 0.05
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Maximum | Measurement Input, Loss Severity [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.55 0.80
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Weighted Average [Member] | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 1.01 1.72
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Weighted Average [Member] | Measurement Input, Constant Prepayment Rate [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.04 0.04
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Weighted Average [Member] | Measurement Input, Default Rate [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.02 0.02
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | RMBS | Weighted Average [Member] | Measurement Input, Loss Severity [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-sale, Measurement Input 0.48 0.50
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Short-term investments | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Other Short-term Investments $ 709 $ 382
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Short-term investments | Minimum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Instrument, Measurement Input 1.64 1.64
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Short-term investments | Maximum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Instrument, Measurement Input 2.38 1.86
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Short-term investments | Weighted Average [Member] | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Instrument, Measurement Input 1.74 1.77
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Equity Securities [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Equity Securities, FV-NI $ 16 $ 14
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Equity Securities [Member] | Valuation, Cost Approach    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Equity Securities, FV-NI $ 82 $ 56
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Equity Securities [Member] | Minimum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Equity Securities, FV-NI, Measurement Input 13.81 13.70
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Equity Securities [Member] | Maximum | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Equity Securities, FV-NI, Measurement Input 13.81 13.70
Significant
Unobservable
Inputs
(Level 3) | Fair Value, Recurring [Member] | Equity Securities [Member] | Weighted Average [Member] | Measurement Input, Credit Spread [Member] | Valuation Technique, Discounted Cash Flow    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Equity Securities, FV-NI, Measurement Input 13.81 13.70
Quoted Prices in
Active Markets
for Identical
Assets
(Level 1)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale $ 489 $ 164
Other Short-term Investments 245 491
Equity Securities, FV-NI 430 311
Assets, Fair Value Disclosure 1,164 966
Quoted Prices in
Active Markets
for Identical
Assets
(Level 1) | Discontinued Operations, Disposed of by Sale | Hartford Funds Management Group, Inc    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Assets, Fair Value Disclosure 168 179
Quoted Prices in
Active Markets
for Identical
Assets
(Level 1) | ABS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 0 0
Quoted Prices in
Active Markets
for Identical
Assets
(Level 1) | Collateralized Loan Obligations [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 0 0
Quoted Prices in
Active Markets
for Identical
Assets
(Level 1) | CMBS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 0 0
Quoted Prices in
Active Markets
for Identical
Assets
(Level 1) | Corporate    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 0 0
Quoted Prices in
Active Markets
for Identical
Assets
(Level 1) | RMBS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 0 0
Significant
Observable
Inputs
(Level 2)    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 41,932 42,505
Other Short-term Investments 2,912 3,131
Equity Securities, FV-NI 6 5
Assets, Fair Value Disclosure 44,847 45,661
Significant
Observable
Inputs
(Level 2) | Discontinued Operations, Disposed of by Sale | Hartford Funds Management Group, Inc    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Assets, Fair Value Disclosure 256 240
Significant
Observable
Inputs
(Level 2) | ABS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 4,608 4,496
Significant
Observable
Inputs
(Level 2) | Collateralized Loan Obligations [Member]    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 3,160 3,099
Significant
Observable
Inputs
(Level 2) | CMBS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 1,725 2,213
Significant
Observable
Inputs
(Level 2) | Corporate    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale 20,952 20,210
Significant
Observable
Inputs
(Level 2) | RMBS    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Debt Securities, Available-for-Sale $ 5,772 $ 6,171