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Derivative Instruments (Total Fair Value Of Company's Derivative Assets And Liabilities By Instrument And Balance Sheet Location, Before Counterparty Netting) (Detail) (USD $) In Millions, unless otherwise specified | Sep. 30, 2013 | Dec. 31, 2012
--- | --- | ---
Derivative [Line Items] |  |  |  |
Derivative notional amount | $ 33,647 |  | $ 58,640 |
Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 33,647 |  | 58,640 |
Derivative Liabilities [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative liabilities, Total derivatives | (1,597) | [1] | (3,425) | [1]
Derivative Liabilities [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | (1,597) | [1] | (3,425) | [1]
Derivative Assets [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative assets, Total assets | 66 | [1] | 102 | [1]
Derivative Assets [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 66 | [1] | 102 | [1]
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 1,575 |  | 1,637 |
Interest Rate Swap [Member] | Derivative Liabilities [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | (195) | [1] | (290) | [1]
Interest Rate Swap [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 57 | [1] | 94 | [1]
Credit Default Swap [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 25,771 |  | 47,320 |
Credit Default Swap [Member] | Derivative Liabilities [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | (1,355) | [1] | (2,858) | [1]
Credit Default Swap [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 0 | [1] | 0 | [1]
Insured Swaps [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 5,363 |  | 5,817 |
Insured Swaps [Member] | Derivative Liabilities [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | (7) | [1] | (8) | [1]
Insured Swaps [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 0 | [1] | 0 | [1]
Non Insured Credit Default Swaps [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 0 |  | 10 |
Non Insured Credit Default Swaps [Member] | Derivative Liabilities [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | 0 | [1] | 0 | [1]
Non Insured Credit Default Swaps [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 0 | [1] | 0 | [1]
Non Insured Credit Default Swaps V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 0 |  | 0 |
Non Insured Credit Default Swaps V I E [Member] | Derivative Liabilities V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | 0 | [1] | 0 | [1]
Non Insured Credit Default Swaps V I E [Member] | Other Assets V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 0 | [1] | 0 | [1]
Interest Rate Swaps V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 0 |  | 2,728 |
Interest Rate Swaps V I E [Member] | Derivative Liabilities V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | 0 | [1] | (141) | [1]
Interest Rate Swaps V I E [Member] | Other Assets V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 0 | [1] | 0 | [1]
Interest Rate Swaps Embedded [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 490 |  | 483 |
Interest Rate Swaps Embedded [Member] | Medium Term Notes [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 9 | [1] | 8 | [1]
Derivative Liabilities, Not designated, Fair Value | (16) | [1] | (35) | [1]
Currency Swap [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 20 |  | 40 |
Currency Swap [Member] | Derivative Liabilities [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | (1) | [1] | (3) | [1]
Currency Swap [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 0 | [1] | 0 | [1]
Currency Swaps Vie [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 102 |  | 110 |
Currency Swaps Vie [Member] | Derivative Liabilities V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | (15) | [1] | (21) | [1]
Currency Swaps Vie [Member] | Other Assets V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 0 | [1] | 0 | [1]
All Other [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 36 |  | 195 |
All Other [Member] | Derivative Liabilities [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | (8) | [1] | (68) | [1]
All Other [Member] | Other Assets [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 0 | [1] | 0 | [1]
All Other V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 280 |  | 280 |
All Other V I E [Member] | Derivative Liabilities V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | 0 | [1] | 0 | [1]
All Other V I E [Member] | Other Assets V I E [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | 0 | [1] | 0 | [1]
All Other Embedded [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative notional amount | 10 |  | 20 |
All Other Embedded [Member] | Derivative Liabilities Other Investments [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Liabilities, Not designated, Fair Value | 0 | [1] | (1) | [1]
All Other Embedded [Member] | Derivative Assets Other Investments [Member] | Not Designated as Hedging Instrument [Member] |  |  |  |
Derivative [Line Items] |  |  |  |
Derivative Assets, Not designated, Fair Value | $ 0 | [1] | $ 0 | [1]
[1] | In accordance with the accounting guidance for derivative instruments and hedging activities, the balance sheet location of the Company’s embedded derivative instruments is determinedby the location of the related host contract.

X
- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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- Definition Fair value of derivative Asset Not Designated As Hedging Instrument, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. + References No definition available. + Details
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- Definition Fair value of derivative liability Not Designated As Hedging Instrument, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. + References No definition available. + Details
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- Definition Fair value before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226000-175313 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959 + Details
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- Definition Fair value before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226000-175313 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959 + Details
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