v3.24.2.u1
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, 2024
Dec. 31, 2023
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis $ 1,862 $ 2,094
Fair value financial liabilities measured on recurring basis 77 134
Money Market Securities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 113 34
Medium-term Notes [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis 36 40
Equity investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 95 155
Cash and Cash Equivalents [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 195 104
Fixed Maturities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 1,426 1,739
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 510 712
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 108 123
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 18 18
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 466 497
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 121 149
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 34 34
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 11 14
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 122 146
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 36 46
Assets Of Consolidated V I Es [Member] | Residential Mortgage Backed Non Agency [Member] | Mortgage-backed [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   10
Assets Of Consolidated V I Es [Member] | Commercial Mortgage Backed Securities [Member] | Mortgage-backed [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   10
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   1
Assets Of Consolidated V I Es [Member] | Other Asset Backed [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   1
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 31 35
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
Assets Of Consolidated V I Es [Member] | Other [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   2
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
Other Liabilities [Member] | Interest rate derivatives [Member] | Non-insured interest rate derivatives [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis   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 9 14
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 31 78
Fair Value Inputs Level 1 [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 863 885
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 113 34
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 43 39
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 195 104
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 510 705
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 510 705
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 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] | Residential Mortgage Backed Non Agency [Member] | Mortgage-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] | Commercial Mortgage Backed Securities [Member] | Mortgage-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] | 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] | Other Asset Backed [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] | Assets Of Consolidated V I Es [Member] | Other [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] | 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] | Other Liabilities [Member] | Interest rate derivatives [Member] | Non-insured interest rate derivatives [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis   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 913 1,063
Fair value financial liabilities measured on recurring basis 1 2
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 7 8
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 906 1,033
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 7
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 108 123
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 18 18
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 456 496
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 121 149
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 34 34
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 11 14
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 122 146
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 36 46
Fair Value Inputs Level 2 [Member] | Assets Of Consolidated V I Es [Member] | Residential Mortgage Backed Non Agency [Member] | Mortgage-backed [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   10
Fair Value Inputs Level 2 [Member] | Assets Of Consolidated V I Es [Member] | Commercial Mortgage Backed Securities [Member] | Mortgage-backed [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   10
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   1
Fair Value Inputs Level 2 [Member] | Assets Of Consolidated V I Es [Member] | Other Asset Backed [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   1
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] | Assets Of Consolidated V I Es [Member] | Other [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 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] | Other Liabilities [Member] | Interest rate derivatives [Member] | Non-insured interest rate derivatives [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis   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 86 146
Fair value financial liabilities measured on recurring basis 76 132
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 36 40
Fair Value Inputs Level 3 [Member] | Equity investments [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis 45 108
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 10 1
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 10 [1] 1
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 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] | Residential Mortgage Backed Non Agency [Member] | Mortgage-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] | Commercial Mortgage Backed Securities [Member] | Mortgage-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] | 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] | Other Asset Backed [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 31 35
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] | Assets Of Consolidated V I Es [Member] | Other [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial assets measured on recurring basis   2
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] | Other Liabilities [Member] | Interest rate derivatives [Member] | Non-insured interest rate derivatives [Member]    
Accounts Notes And Loans Receivable [Line Items]    
Fair value financial liabilities measured on recurring basis   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 9 14
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 $ 31 $ 78
[1] Includes loans carried at fair value of $9 million.