| **Fair Value Measurements - Fair Values of Deferred Annuities, Structured Settlements and Other Items (Detail) (USD $)In Millions, unless otherwise specified** | Sep. 30, 2013 | Dec. 31, 2012 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | $ 1,099       | $ 1,138       |
| Deferred Annuities                                                                                                                                              |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 881           | 898           |
| Structured Settlements                                                                                                                                          |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 218           | 240           |
| Quoted prices in active markets for identical assets (Level 1)                                                                                                  |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 0             | 0             |
| Quoted prices in active markets for identical assets (Level 1) | Deferred Annuities                                                                             |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 0             | 0             |
| Quoted prices in active markets for identical assets (Level 1) | Structured Settlements                                                                         |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 0             | 0             |
| Significant other observable inputs (Level 2)                                                                                                                   |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 218           | 240           |
| Significant other observable inputs (Level 2) | Deferred Annuities                                                                                              |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 0             | 0             |
| Significant other observable inputs (Level 2) | Structured Settlements                                                                                          |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 218           | 240           |
| Significant unobservable inputs (Level 3)                                                                                                                       |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 881           | 898           |
| Significant unobservable inputs (Level 3) | Deferred Annuities                                                                                                  |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | 881           | 898           |
| Significant unobservable inputs (Level 3) | Structured Settlements                                                                                              |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]**                                                                |          |          |
| Fair Value of life insurance liabilities                                                                                                                        | $ 0           | $ 0           |

| X                                                                                                                                                                                                                 |
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
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| - Definition
Fair value portion of liability related to investment contracts for example, but not limited to, guaranteed investment contract or annuities.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 825 -Section 25 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6487514&loc=d3e32427-158581Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 14 -Article 7
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