v3.25.2
Fair Value of Financial Instruments (Company's Assets And Liabilities Measured At Fair Value On Recurring Basis) (Detail) - Fair Value Measurements Recurring [Member] - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis $ 1,746 $ 1,769
Fair value financial liabilities measured on recurring basis 75 73
Money Market Securities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 49 181
Medium-term Notes [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 38 35
Equity investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 109 [1] 117 [2]
Cash and Cash Equivalents [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 165 84
Fixed Maturities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 1,388 1,356
Fixed Maturities [Member] | U.S. Treasury And Government Agency [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 524 481
Fixed Maturities [Member] | State and municipal bonds [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 99 102
Fixed Maturities [Member] | Foreign Government Debt [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 5 10
Fixed Maturities [Member] | Corporate Obligations [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 402 451
Fixed Maturities [Member] | Residential Mortgage Backed Agency [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 117 111
Fixed Maturities [Member] | Residential Mortgage Backed Non Agency [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 15 41
Fixed Maturities [Member] | Commercial Mortgage Backed Securities [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 19 7
Fixed Maturities [Member] | Collateralized Debt Obligations [Member] | Asset-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 61  
Fixed Maturities [Member] | Other Asset Backed [Member] | Asset-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 146 52
Assets Of Consolidated V I Es [Member] | Collateralized Debt Obligations [Member] | Asset-backed [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   101
Assets Of Consolidated V I Es [Member] | Loans Receivable and Other Instruments At Fair Value [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Residential Loans Receivable [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 33 28
Assets Of Consolidated V I Es [Member] | Cash and Cash Equivalents [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 2 3
Other Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 1 1
Liabilities Of Consolidated Vies [Member] | Currency Derivatives [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 10 6
Liabilities Of Consolidated Vies [Member] | Variable Interest Entity Notes [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 26 31
Fair Value Inputs Level 1 [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 781 797
Fair value financial liabilities measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Money Market Securities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 49 181
Fair Value Inputs Level 1 [Member] | Medium-term Notes [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Equity investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 41 48
Fair Value Inputs Level 1 [Member] | Cash and Cash Equivalents [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 165 84
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 524 481
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | U.S. Treasury And Government Agency [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 524 481
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | State and municipal bonds [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | Foreign Government Debt [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | Corporate Obligations [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | Residential Mortgage Backed Agency [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | Residential Mortgage Backed Non Agency [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | Commercial Mortgage Backed Securities [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | Collateralized Debt Obligations [Member] | Asset-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0  
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | Other Asset Backed [Member] | Asset-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Assets Of Consolidated V I Es [Member] | Collateralized Debt Obligations [Member] | Asset-backed [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   0
Fair Value Inputs Level 1 [Member] | Assets Of Consolidated V I Es [Member] | Loans Receivable and Other Instruments At Fair Value [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Residential Loans Receivable [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Assets Of Consolidated V I Es [Member] | Cash and Cash Equivalents [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 2 3
Fair Value Inputs Level 1 [Member] | Other Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Liabilities Of Consolidated Vies [Member] | Currency Derivatives [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 0 0
Fair Value Inputs Level 1 [Member] | Liabilities Of Consolidated Vies [Member] | Variable Interest Entity Notes [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 0 0
Fair Value Inputs Level 2 [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 854 866
Fair value financial liabilities measured on recurring basis 1 1
Fair Value Inputs Level 2 [Member] | Money Market Securities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 2 [Member] | Medium-term Notes [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 0 0
Fair Value Inputs Level 2 [Member] | Equity investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 6 7
Fair Value Inputs Level 2 [Member] | Cash and Cash Equivalents [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 848 859
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | U.S. Treasury And Government Agency [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | State and municipal bonds [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 99 102
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | Foreign Government Debt [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 5 10
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | Corporate Obligations [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 386 435
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | Residential Mortgage Backed Agency [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 117 111
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | Residential Mortgage Backed Non Agency [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 15 41
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | Commercial Mortgage Backed Securities [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 19 7
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | Collateralized Debt Obligations [Member] | Asset-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 61  
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | Other Asset Backed [Member] | Asset-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 146 52
Fair Value Inputs Level 2 [Member] | Assets Of Consolidated V I Es [Member] | Collateralized Debt Obligations [Member] | Asset-backed [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   101
Fair Value Inputs Level 2 [Member] | Assets Of Consolidated V I Es [Member] | Loans Receivable and Other Instruments At Fair Value [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Residential Loans Receivable [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 2 [Member] | Assets Of Consolidated V I Es [Member] | Cash and Cash Equivalents [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 2 [Member] | Other Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 1 1
Fair Value Inputs Level 2 [Member] | Liabilities Of Consolidated Vies [Member] | Currency Derivatives [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 0 0
Fair Value Inputs Level 2 [Member] | Liabilities Of Consolidated Vies [Member] | Variable Interest Entity Notes [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 101 96
Fair value financial liabilities measured on recurring basis 74 72
Fair Value Inputs Level 3 [Member] | Money Market Securities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Medium-term Notes [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 38 35
Fair Value Inputs Level 3 [Member] | Equity investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 52 52
Fair Value Inputs Level 3 [Member] | Cash and Cash Equivalents [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 16 16
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | U.S. Treasury And Government Agency [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | State and municipal bonds [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | Foreign Government Debt [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | Corporate Obligations [Member] | Other Fixed Maturity Investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 16 [3] 16 [4]
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | Residential Mortgage Backed Agency [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | Residential Mortgage Backed Non Agency [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | Commercial Mortgage Backed Securities [Member] | Mortgage-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | Collateralized Debt Obligations [Member] | Asset-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0  
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | Other Asset Backed [Member] | Asset-backed [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Assets Of Consolidated V I Es [Member] | Collateralized Debt Obligations [Member] | Asset-backed [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   0
Fair Value Inputs Level 3 [Member] | Assets Of Consolidated V I Es [Member] | Loans Receivable and Other Instruments At Fair Value [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Residential Loans Receivable [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 33 28
Fair Value Inputs Level 3 [Member] | Assets Of Consolidated V I Es [Member] | Cash and Cash Equivalents [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Other Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 0 0
Fair Value Inputs Level 3 [Member] | Liabilities Of Consolidated Vies [Member] | Currency Derivatives [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 10 6
Fair Value Inputs Level 3 [Member] | Liabilities Of Consolidated Vies [Member] | Variable Interest Entity Notes [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis $ 26 $ 31
[1] Includes $10 million of an exchange-traded bond fund that seeks to track the investment results of an index composed of U.S. dollar-denominated, high yield corporate bonds. The fund is measured at fair value by applying the net asset value per share practical expedient, and is not required to be classified in the fair value hierarchy.
[2] Includes $10 million of an exchange-traded bond fund that seeks to track the investment results of an index composed of U.S. dollar-denominated, high yield corporate bonds. The fund is measured at fair value by applying the net asset value per share practical expedient, and is not required to be classified in the fair value hierarchy.
[3] Includes loans carried at fair value of $15 million.
[4] Includes loans carried at fair value of $15 million.