| **Fair Value Measurements - Fair Value of Life Policy Loans (Detail) - USD ($) $ in Millions**   | Jun. 30, 2015 | Dec. 31, 2014 |
|--------------------------------------------------------------------------------------------------|---------------|---------------|
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]** |          |          |
| Fair value of life policy loans                                                                  | $ 41          | $ 39          |
| 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 policy loans                                                                  | 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 policy loans                                                                  | 0             | 0             |
| Significant unobservable inputs (Level 3)                                                        |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]** |          |          |
| Fair value of life policy loans                                                                  | $ 41          | $ 39          |

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| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
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| - Definition
Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Glossary Loan -URI http://asc.fasb.org/extlink&oid=6517073
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