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Recent Developments Related to COVID-19 Income Statement (Narrative) (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
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Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019
Income Statement [Abstract] |  |  |  |
Net investment gains (losses) | $ 911,243 | $ 425,653 | $ (770,198) | $ 1,037,844
Change in fair value of equity securities | $ 914,055 | $ 425,720 | $ (777,124) | $ 1,037,230

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- Definition The net gains or losses on investments during the period, also including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity. + References No definition available. + Details
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- Definition Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714 + Details
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- References No definition available. + Details
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