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Fair Value Of Financial Instruments (Quantitative Information Regarding The Significant Unobservable Inputs For Certain Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2012 | Mar. 31, 2011 | Dec. 31, 2011 | Dec. 31, 2010
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value | $ 3,937 | $ 4,439 | $ 4,188 | $ 4,467
Fair value, liabilities | 7,622 | 11,821 | 7,938 | 9,916
(Decrease) increase in accrued interest payable | (25) | (22) |  |
Loans Receivable [Member] | Variable Interest Entity [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value | 2,025 | 2,327 | 2,046 | 2,183
Valuation Technique | Quoted market prices adjusted for financial guarantees provided to VIE obligations |  |  |
Loan Repurchase Commitments [Member] | Variable Interest Entity [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value | 1,076 | 867 | 1,077 | 835
Valuation Technique | Discounted cash flow |  |  |
Variable Interest Entity Notes [Member] | Variable Interest Entity [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair value, liabilities | 2,864 |  |  |
Valuation Technique | Quoted market prices of VIE assets adjusted for financial guarantees provided |  |  |
Commercial Mortgage-Backed [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value | 25 | 51 | 24 | 41
Commercial Mortgage-Backed [Member] | Variable Interest Entity [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value | 15 | 29 | 22 | 23
Commercial Mortgage-Backed [Member] | Credit Derivatives [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value | 2,183 |  |  |
Valuation Technique | BET Model |  |  |
Multi-Sector CDO [Member] | Credit Derivatives [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value | 928 |  |  |
Valuation Technique | Direct Price Model |  |  |
Other Assets [Member] | Credit Derivatives [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value | $ 1,376 |  |  |
Valuation Technique | BET Model |  |  |
Impact Of Financial Guarantee [Member] | Loans Receivable [Member] | Variable Interest Entity [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum | 0.00% |  |  |
Range, maximum | 114.00% |  |  |
Weighted Average | 7.00% |  |  |
Impact Of Financial Guarantee [Member] | Variable Interest Entity Notes [Member] | Variable Interest Entity [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum | 0.00% |  |  |
Range, maximum | 26.00% |  |  |
Weighted Average | 3.00% |  |  |
Recovery Rates [Member] | Loan Repurchase Commitments [Member] | Variable Interest Entity [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum | 25.00% |  |  |
Range, maximum | 75.00% |  |  |
Weighted Average | 71.00% |  |  |
Recovery Rates [Member] | Commercial Mortgage-Backed [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum | 22.00% |  |  |
Range, maximum | 90.00% |  |  |
Weighted Average | 50.00% |  |  |
Recovery Rates [Member] | Other Assets [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum | 42.00% |  |  |
Range, maximum | 75.00% |  |  |
Weighted Average | 47.00% |  |  |
Breach Rate [Member] | Loan Repurchase Commitments [Member] | Variable Interest Entity [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum | 65.00% |  |  |
Range, maximum | 94.00% |  |  |
Weighted Average | 76.00% |  |  |
Nonperformance Risk [Member] | Commercial Mortgage-Backed [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum | 4.00% |  |  |
Range, maximum | 57.00% |  |  |
Weighted Average | 49.00% |  |  |
Nonperformance Risk [Member] | Multi-Sector CDO [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum | 57.00% |  |  |
Range, maximum | 57.00% |  |  |
Weighted Average | 57.00% |  |  |
Nonperformance Risk [Member] | Other Assets [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum | 10.00% |  |  |
Range, maximum | 57.00% |  |  |
Weighted Average | 44.00% |  |  |
Weighted Average Life [Member] | Commercial Mortgage-Backed [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum (in years) | 0.2 |  |  |
Range, maximum (in years) | 6.4 |  |  |
Weighted average (in years) | 4.7 |  |  |
Weighted Average Life [Member] | Other Assets [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum (in years) | 0.2 |  |  |
Range, maximum (in years) | 13.4 |  |  |
Weighted average (in years) | 3.1 |  |  |
CMBS Spreads [Member] | Commercial Mortgage-Backed [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Range, minimum (in percentage) | 1.00% |  |  |
Range, maximum (in percentage) | 23.00% |  |  |
Weighted average (in percentage) | 12.00% |  |  |

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- Definition This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
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- Definition This element represents a liability measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 + Details
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- Definition The increase (decrease) during the reporting period in interest payable, which represents the amount owed to note holders, bond holders, and other parties for interest earned on loans or credit extended to the reporting entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585 + Details
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