Investments - Summary of Sale Activity of Available-for-Sale-Securities (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
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Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
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| Amortized Cost And Fair Value Debt Securities [Abstract] | |||
| Sales proceeds | $ 36 | $ 155 | $ 139 |
| Gross realized gains | 3 | 14 | 20 |
| Gross realized losses | (1) | (3) | (1) |
| Net realized gain (loss) | $ 2 | $ 11 | $ 19 |
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- Definition Amortized Cost and Fair Value Debt Securities [Abstract] No definition available.
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- Definition This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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