| **Accumulated Other Comprehensive Income (Loss) by Component (Tables)**  | 3 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 January 1, 2015$36 $942 $(633) $55 $400Other comprehensive income (loss) before reclassifications(1) 121 — (96) 24Amounts reclassified from Accumulated other comprehensive income (loss) after tax (expense) benefit of $0, $0, $3, $0 and $3— 9 (6) — 3Other comprehensive income (loss) after tax (expense) benefit of $0, $(62), $(3), $0 and $(65)(1) 112 6 (96) 21Balance as of March 31, 2015$35 $1,054 $(627) $(41) $421(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 reclassifications12 264 8 — (8) 276Amounts reclassified from Accumulated other comprehensive income (loss) after tax (expense) benefit of $0, $(14), $0, $1, $0 and $(13)— 27 — (1) — 26Other comprehensive income (loss) after tax (expense) benefit of $(6), $(127), $(5), $(1), $0 and $(139)12 237 8 1 (8) 250Balance as of March 31, 2014$33 $912 $30 $(425) $142 $692 |

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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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