| **Derivative Financial Instruments**             | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
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| **Summary of Derivative Instruments [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| Derivative Financial Instruments                 | Note E. Derivative Financial InstrumentsA summary of the recognized gains (losses) related to derivative financial instruments follows.Recognized Gains (Losses)Periods ended September 30Three Months Nine Months(In millions)2012 2011 2012 2011Without hedge designation       Currency forwards$(1) $— $(1) $(1)Forward commitments for mortgage-backed securities— 1 — 1Total without hedge designation(1) 1 (1) —Trading activities       Futures sold, not yet purchased(1) — — —Total$(2) $1 $(1) $—A summary of the aggregate contractual or notional amounts and gross estimated fair values related to derivative financial instruments reported as Other invested assets or Other liabilities on the Condensed Consolidated Balance Sheets follows.  The contractual or notional amounts for derivatives are used to calculate the exchange of contractual payments under the agreements and may not be representative of the potential for gain or loss on these instruments.Derivative Financial InstrumentsSeptember 30, 2012Contractual/NotionalAmount Estimated Fair Value(In millions) Asset (Liability)Without hedge designation     Credit default swaps - purchased protection$20 $— $(1)Currency forwards72 — (2)Equity warrants5 — —Total$97 $— $(3)December 31, 2011Contractual/NotionalAmount Estimated Fair Value(In millions) Asset (Liability)Without hedge designation     Credit default swaps - purchased protection$20 $— $(1)Currency forwards22 1 —Equity warrants4 — —Total$46 $1 $(1)During the three and nine months ended September 30, 2012, new derivative transactions entered into totaled $472 million and $1,251 million in notional value while derivative termination activity totaled $488 million and $1,200 million.  This activity was primarily attributable to interest rate futures, forward commitments for mortgage-backed securities and foreign currency forwards.  During the three and nine months ended September 30, 2011, new derivative transactions entered into totaled approximately $229 million and $728 million in notional value while derivative termination activity totaled approximately $166 million and $673 million.  This activity was primarily attributable to interest rate futures, forward commitments for mortgage-backed securities and foreign currency forwards. |

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| - Definition
The entire disclosure for the entity's entire derivative instruments and hedging activities.  Describes an entity's risk management strategies, derivatives in hedging activities and non-hedging derivative instruments, the assets, obligations, liabilities, revenues and expenses arising therefrom, and the amounts of and methodologies and assumptions used in determining the amounts of such items.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44 -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 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5580258-113959Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(n)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5618551-113959Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624163-113959Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4J -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5708773-113959Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6935481&loc=d3e41638-113959Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6935481&loc=d3e41620-113959Reference 10: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6935481&loc=d3e41641-113959Reference 11: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80748-113994Reference 12: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6441202&loc=d3e80720-113993Reference 13: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6887037&loc=d3e80784-113994Reference 14: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5579240-113959Reference 15: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6935481&loc=d3e41635-113959Reference 16: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4E -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624181-113959Reference 17: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4H -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624258-113959Reference 18: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5579245-113959Reference 19: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 25 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986Reference 20: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 45 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  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