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	Sep. 30, 2023	Dec. 31, 2022
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	$ 2,475	$ 2,890
Fair value financial liabilities measured on recurring basis	149	268
Money Market Securities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	338	234
Medium-term Notes [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	37	41
Equity investments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	171	172
Cash and Cash Equivalents [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	70	50
Fixed Maturities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	1,836	2,270
Fixed Maturities [Member] | U S Treasury And Government [Member] | Other Fixed Maturity Investments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	431	517
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	118	323
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	22	21
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	800	797
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	183	207
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	95
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	22	24
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	161	159
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	65	127
Assets Of Consolidated V I Es [Member] | Corporate Obligations [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis		4
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	11	22
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	9	9
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	5
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	7
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	32	78
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	4	16
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	23
Derivative Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	1
Derivative 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	22	49
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	11	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	78	172
Fair Value Inputs Level 1 [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	828	801
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	338	234
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	37	38
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	70	50
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	379	463
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | U S Treasury And Government [Member] | Other Fixed Maturity Investments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	379	463
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] | Corporate Obligations [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] | 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	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	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	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	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	4	16
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	0
Fair Value Inputs Level 1 [Member] | Derivative Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0
Fair Value Inputs Level 1 [Member] | Derivative 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	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	1,497	1,873
Fair value financial liabilities measured on recurring basis	23	49
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	19	19
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	1,456	1,807
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | U S Treasury And Government [Member] | Other Fixed Maturity Investments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	52	54
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	118	323
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	22	21
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	799	797
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	183	207
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	95
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	22	24
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	161	159
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	65	127
Fair Value Inputs Level 2 [Member] | Assets Of Consolidated V I Es [Member] | Corporate Obligations [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis		4
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	11	22
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	9	9
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	5
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	7
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	0
Fair Value Inputs Level 2 [Member] | Derivative Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	1
Fair Value Inputs Level 2 [Member] | Derivative 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	22	49
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	150	216
Fair value financial liabilities measured on recurring basis	126	219
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	37	41
Fair Value Inputs Level 3 [Member] | Equity investments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	115	115
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	1	0
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | U S Treasury And Government [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	1	0
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] | Corporate Obligations [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] | 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	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	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	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	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	32	78
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	23
Fair Value Inputs Level 3 [Member] | Derivative Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0
Fair Value Inputs Level 3 [Member] | Derivative 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	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	11	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	$ 78	$ 172