Fair Value Of Financial Instruments (Company's Assets And Liabilities Measured At Fair Value On Recurring Basis) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	$ 10,786	$ 12,174
Fair value financial liabilities measured on recurring basis	3,781	6,926
Variable Interest Entity Primary Beneficiary [Member] | Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	1,612	1,881
Variable Interest Entity Primary Beneficiary [Member] | Loan Repurchase Commitments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	359	1,086
State and municipal bonds [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	41
Corporate Obligations [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	89	293
Residential Mortgage Backed 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
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	259	875
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	105	417
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	36	340
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	98	184
Money Market Securities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	783	593
Money Market Securities [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	136	210
Medium Term Notes [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	203	165
Perpetual Debt And Equity Securities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	51	57
Cash And Cash Equivalents [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	1,161	814
Fixed Maturities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	5,996	5,203
Fixed Maturities [Member] | U S Treasury And Government [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	553	884
Fixed Maturities [Member] | State and municipal bonds [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	1,784	1,532
Fixed Maturities [Member] | Foreign Government Debt [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	189	196
Fixed Maturities [Member] | Corporate Obligations [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	1,824	1,216
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	1,173	988
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	92	98
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	39	48
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	154	96
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	188	145
Derivative Assets [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	4	4
Derivative Assets [Member] | Credit Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Derivative Assets [Member] | Credit Derivatives [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Derivative Assets [Member] | Interest Rate Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	4	4
Derivative Assets [Member] | Interest Rate Derivatives [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Derivative Assets [Member] | Other Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Assets Of Consolidated V I Es [Member] | Cash And Cash Equivalents [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	97	176
Derivative Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	1,152	2,934
Derivative Liabilities [Member] | Credit Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0
Derivative Liabilities [Member] | Credit 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
Derivative Liabilities [Member] | Interest Rate Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	(2)
Derivative Liabilities [Member] | Interest Rate Derivatives [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	141
Derivative Liabilities [Member] | Currency Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	2
Derivative Liabilities [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	21
Derivative Liabilities [Member] | Other Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	0
Other Liabilities [Member] | Warrant [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	59	6
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	2,356	3,659
Fair Value Inputs Level 1 [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	2,713	2,678
Fair value financial liabilities measured on recurring basis	0	0
Fair Value Inputs Level 1 [Member] | Variable Interest Entity Primary Beneficiary [Member] | 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] | Variable Interest Entity Primary Beneficiary [Member] | Loan Repurchase Commitments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Fair Value Inputs Level 1 [Member] | State and municipal bonds [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] | 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	0
Fair Value Inputs Level 1 [Member] | Residential Mortgage Backed 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] | 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] | 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] | 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] | 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] | Money Market Securities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	783	585
Fair Value Inputs Level 1 [Member] | Money Market Securities [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	136	210
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] | Perpetual Debt And Equity Securities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	27	23
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	1,161	814
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	509	870
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | U S Treasury And Government [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	397	784
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | State and municipal bonds [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]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	112	86
Fair Value Inputs Level 1 [Member] | Fixed Maturities [Member] | Corporate Obligations [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] | Derivative Assets [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 Assets [Member] | Credit Derivatives [Member] | Non Insured Derivatives [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 Assets [Member] | Credit Derivatives [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 Assets [Member] | Interest Rate Derivatives [Member] | Non Insured Derivatives [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 Assets [Member] | Interest Rate Derivatives [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 Assets [Member] | Other Derivatives [Member] | Non Insured Derivatives [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]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	97	176
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	0
Fair Value Inputs Level 1 [Member] | Derivative Liabilities [Member] | Credit Derivatives [Member] | Non 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] | Credit 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] | Derivative Liabilities [Member] | Interest Rate Derivatives [Member] | Non 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] | Derivative Liabilities [Member] | Interest Rate 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] | Derivative Liabilities [Member] | Currency Derivatives [Member] | Non 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] | Derivative Liabilities [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] | Derivative Liabilities [Member] | Other Derivatives [Member] | Non 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] | Warrant [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	0
Fair Value Inputs Level 1 [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	5,763	6,049
Fair value financial liabilities measured on recurring basis	1,645	2,175
Fair Value Inputs Level 2 [Member] | Variable Interest Entity Primary Beneficiary [Member] | 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] | Variable Interest Entity Primary Beneficiary [Member] | Loan Repurchase Commitments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Fair Value Inputs Level 2 [Member] | State and municipal bonds [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	41
Fair Value Inputs Level 2 [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	41	215
Fair Value Inputs Level 2 [Member] | Residential Mortgage Backed 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 2 [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	255	869
Fair Value Inputs Level 2 [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	102	410
Fair Value Inputs Level 2 [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	14	215
Fair Value Inputs Level 2 [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	44	120
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	8
Fair Value Inputs Level 2 [Member] | Money Market Securities [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] | 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] | Perpetual Debt And Equity Securities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	13	20
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	5,248	4,062
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | U S Treasury And Government [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	156	100
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | State and municipal bonds [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	1,765	1,429
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | Foreign Government Debt [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	65	107
Fair Value Inputs Level 2 [Member] | Fixed Maturities [Member] | Corporate Obligations [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	1,776	1,140
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	1,173	988
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	86	94
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	25	20
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	72	65
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	130	119
Fair Value Inputs Level 2 [Member] | Derivative Assets [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	46	89
Fair Value Inputs Level 2 [Member] | Derivative Assets [Member] | Credit Derivatives [Member] | Non Insured Derivatives [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 Assets [Member] | Credit Derivatives [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 Assets [Member] | Interest Rate Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	46	89
Fair Value Inputs Level 2 [Member] | Derivative Assets [Member] | Interest Rate Derivatives [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 Assets [Member] | Other Derivatives [Member] | Non Insured Derivatives [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]
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	5	13
Fair Value Inputs Level 2 [Member] | Derivative Liabilities [Member] | Credit Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0
Fair Value Inputs Level 2 [Member] | Derivative Liabilities [Member] | Credit 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] | Derivative Liabilities [Member] | Interest Rate Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	165	287
Fair Value Inputs Level 2 [Member] | Derivative Liabilities [Member] | Interest Rate Derivatives [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	141
Fair Value Inputs Level 2 [Member] | Derivative Liabilities [Member] | Currency Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	1
Fair Value Inputs Level 2 [Member] | Derivative Liabilities [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] | Derivative Liabilities [Member] | Other Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	0
Fair Value Inputs Level 2 [Member] | Other Liabilities [Member] | Warrant [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	59	6
Fair Value Inputs Level 2 [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	1,416	1,727
Fair Value Inputs Level 3 [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	2,352	3,537
Fair value financial liabilities measured on recurring basis	2,301	5,044
Fair Value Inputs Level 3 [Member] | Variable Interest Entity Primary Beneficiary [Member] | Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	1,612	1,881
Fair Value Inputs Level 3 [Member] | Variable Interest Entity Primary Beneficiary [Member] | Loan Repurchase Commitments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	359	1,086
Fair Value Inputs Level 3 [Member] | State and municipal bonds [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] | Corporate Obligations [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	48	78
Fair Value Inputs Level 3 [Member] | Residential Mortgage Backed 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] | 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	4	6
Fair Value Inputs Level 3 [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	3	7
Fair Value Inputs Level 3 [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	22	125
Fair Value Inputs Level 3 [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	54	64
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] | Money Market Securities [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] | Medium Term Notes [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	203	165
Fair Value Inputs Level 3 [Member] | Perpetual Debt And Equity Securities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	11	14
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	239	271
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | U S Treasury And Government [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]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	19	103
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | Foreign Government Debt [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	12	3
Fair Value Inputs Level 3 [Member] | Fixed Maturities [Member] | Corporate Obligations [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	48	76
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	6	4
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	14	28
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	82	31
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	58	26
Fair Value Inputs Level 3 [Member] | Derivative Assets [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	5
Fair Value Inputs Level 3 [Member] | Derivative Assets [Member] | Credit Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Fair Value Inputs Level 3 [Member] | Derivative Assets [Member] | Credit Derivatives [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] | Derivative Assets [Member] | Interest Rate Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	5
Fair Value Inputs Level 3 [Member] | Derivative Assets [Member] | Interest Rate Derivatives [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] | Derivative Assets [Member] | Other Derivatives [Member] | Non Insured Derivatives [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] | 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] | Derivative Liabilities [Member] | Credit Derivatives [Member] | Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	1,147	2,921
Fair Value Inputs Level 3 [Member] | Derivative Liabilities [Member] | Credit Derivatives [Member] | Non 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] | Credit 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 3 [Member] | Derivative Liabilities [Member] | Interest Rate Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	4
Fair Value Inputs Level 3 [Member] | Derivative Liabilities [Member] | Interest Rate 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 3 [Member] | Derivative Liabilities [Member] | Currency Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	1
Fair Value Inputs Level 3 [Member] | Derivative Liabilities [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	21
Fair Value Inputs Level 3 [Member] | Derivative Liabilities [Member] | Other Derivatives [Member] | Non 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] | Warrant [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	0
Fair Value Inputs Level 3 [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	940	1,932
Counterparty And Cash Collateral Netting [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	(42)	(90)
Fair value financial liabilities measured on recurring basis	(165)	(293)
Counterparty And Cash Collateral Netting [Member] | Variable Interest Entity Primary Beneficiary [Member] | Loans Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Variable Interest Entity Primary Beneficiary [Member] | Loan Repurchase Commitments [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | State and municipal bonds [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [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	0
Counterparty And Cash Collateral Netting [Member] | Residential Mortgage Backed 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
Counterparty And Cash Collateral Netting [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
Counterparty And Cash Collateral Netting [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
Counterparty And Cash Collateral Netting [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
Counterparty And Cash Collateral Netting [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
Counterparty And Cash Collateral Netting [Member] | Money Market Securities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Money Market Securities [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Medium Term Notes [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Perpetual Debt And Equity Securities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Cash And Cash Equivalents [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Fixed Maturities [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Fixed Maturities [Member] | U S Treasury And Government [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Fixed Maturities [Member] | State and municipal bonds [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Fixed Maturities [Member] | Foreign Government Debt [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Fixed Maturities [Member] | Corporate Obligations [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [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
Counterparty And Cash Collateral Netting [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
Counterparty And Cash Collateral Netting [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
Counterparty And Cash Collateral Netting [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
Counterparty And Cash Collateral Netting [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
Counterparty And Cash Collateral Netting [Member] | Derivative Assets [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	(42)	(90)
Counterparty And Cash Collateral Netting [Member] | Derivative Assets [Member] | Credit Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Derivative Assets [Member] | Credit Derivatives [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Derivative Assets [Member] | Interest Rate Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	(42)	(90)
Counterparty And Cash Collateral Netting [Member] | Derivative Assets [Member] | Interest Rate Derivatives [Member] | Variable Interest Entity Primary Beneficiary [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Derivative Assets [Member] | Other Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Assets Of Consolidated V I Es [Member] | Cash And Cash Equivalents [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial assets measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [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	0
Counterparty And Cash Collateral Netting [Member] | Derivative Liabilities [Member] | Credit Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0
Counterparty And Cash Collateral Netting [Member] | Derivative Liabilities [Member] | Credit 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
Counterparty And Cash Collateral Netting [Member] | Derivative Liabilities [Member] | Interest Rate Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	(165)	(293)
Counterparty And Cash Collateral Netting [Member] | Derivative Liabilities [Member] | Interest Rate 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
Counterparty And Cash Collateral Netting [Member] | Derivative Liabilities [Member] | Currency Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Derivative Liabilities [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
Counterparty And Cash Collateral Netting [Member] | Derivative Liabilities [Member] | Other Derivatives [Member] | Non Insured Derivatives [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [Member] | Other Liabilities [Member] | Warrant [Member]
Accounts Notes And Loans Receivable [Line Items]
Fair value financial liabilities measured on recurring basis	0	0
Counterparty And Cash Collateral Netting [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