| **Quarterly Supplementary Data**                          | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
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| **Quarterly Financial Information Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Quarterly Supplementary Data                              | Quarterly Supplementary DataThis table includes unaudited quarterly financial information for the years ended December 31, 2014 and 2013:(Dollars in millions except per share data) Quarter    1st 2nd 3rd 4th Full year2014          Revenues  $1,189 $1,214 $1,280 $1,262 $4,945Income before income taxes 119 107 259 236 721Net income 91 84 183 167 525Net income per common share—basic 0.56 0.51 1.12 1.03 3.21Net income per common share—diluted 0.55 0.51 1.11 1.02 3.18           2013          Revenues  $1,103 $1,104 $1,152 $1,172 $4,531Income before income taxes 217 148 182 167 714Net income  154 110 131 122 517Net income per common share—basic 0.95 0.67 0.80 0.75 3.16Net income per common share—diluted 0.94 0.66 0.79 0.74 3.12            Note: The sum of the quarterly reported per share amounts may not equal the full year as each is computed independently. Revenues including realized investment gains and losses, which are integral to our financial results over the long term, may cause this value to fluctuate substantially because we have substantial discretion in the timing of investment sales. Also, applicable accounting standards require us to recognize gains and losses from certain changes in fair values of securities and embedded derivatives without actual realization of those gains and losses.   |

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| - Definition
The entire disclosure for the quarterly financial data in the annual financial statements.  The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.
+ References
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