| **Accumulated Other Comprehensive Income (Loss) by Component (Tables)**  | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
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| **Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| Accumulated Other Comprehensive Income (Loss) by Component               | The following tables present the changes in Accumulated other comprehensive income (loss) by component.(In millions)Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment TotalBalance as of July 1, 2015$31 $689 $(585) $8 $143Other comprehensive income (loss) before reclassifications2 (67) — (53) (118)Amounts reclassified from Accumulated other comprehensive income (loss) after tax (expense) benefit of $-, $17, $2, $- and $19— (31) (4) — (35)Other comprehensive income (loss) after tax (expense) benefit of $(1), $21, $(2), $- and $182 (36) 4 (53) (83)Balance as of September 30, 2015$33 $653 $(581) $(45) $60(In millions)Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Net unrealized gains (losses) on discontinued operations Pension and postretirement benefits Cumulative foreign currency translation adjustment TotalBalance as of July 1, 2014$35 $1,182 $37 $(476) $184 $962Other comprehensive income (loss) before reclassifications1 (59) (3) (2) (73) (136)Amounts reclassified from Accumulated other comprehensive income (loss) after tax (expense) benefit of $-, $(12), $(23), $2, $- and $(33)— 24 34 (5) — 53Other comprehensive income (loss) after tax (expense) benefit of $(1), $64, $25, $(1), $- and $871 (83) (37) 3 (73) (189)Balance as of September 30, 2014$36 $1,099 $— $(473) $111 $773(In millions)Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment TotalBalance as of January 1, 2015$36 $942 $(633) $55 $400Other comprehensive income (loss) before reclassifications(3) (318) 36 (100) (385)Amounts reclassified from Accumulated other comprehensive income (loss) after tax (expense) benefit of $-, $22, $9, $- and $31— (29) (16) — (45)Other comprehensive income (loss) after tax (expense) benefit of $1, $140, $(28), $- and $113(3) (289) 52 (100) (340)Balance as of September 30, 2015$33 $653 $(581) $(45) $60(In millions)Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Net unrealized gains (losses) on discontinued operations Pension and postretirement benefits Cumulative foreign currency translation adjustment TotalBalance as of January 1, 2014$26 $692 $— $(426) $150 $442Transfer to net assets held for sale(5) (17) 22 — — —Other comprehensive income (loss) before reclassifications15 462 12 (2) (39) 448Amounts reclassified from Accumulated other comprehensive income (loss) after tax (expense) benefit of $-, $(20), $(23), $(25), $- and $(68)— 38 34 45 — 117Other comprehensive income (loss) after tax (expense) benefit of $(8), $(209), $15, $26, $- and $(176)15 424 (22) (47) (39) 331Balance as of September 30, 2014$36 $1,099 $— $(473) $111 $773 |

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| - References
No definition available.
+ Details**Name:**us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
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| - Definition
Tabular disclosure of the components of accumulated other comprehensive income (loss).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669686-108580
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