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Investments (Fair Value Below Amortized Cost of Gross Unrealized Losses for Fixed Maturity and Equity Securities) (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2020 | Dec. 31, 2019
Gross unrealized losses with number of securities [Line Items] |  |
Document Period End Date | Mar. 31, 2020 |
Gross Unrealized Losses | $ 1,461 | $ 110
% of Total | 100.00% | 100.00%
Less than 20% |  |
Gross unrealized losses with number of securities [Line Items] |  |
Gross Unrealized Losses | $ 1,052 | $ 76
% of Total | 72.00% | 69.10%
20% or more for less than six months |  |
Gross unrealized losses with number of securities [Line Items] |  |
Gross Unrealized Losses | $ 409 | $ 20
% of Total | 28.00% | 18.20%
20% or more for six months or greater |  |
Gross unrealized losses with number of securities [Line Items] |  |
Gross Unrealized Losses | $ 0 | $ 14
% of Total | 0.00% | 12.70%

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- Definition The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is CCYY-MM-DD. + References No definition available. + Details
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- Definition Percentage of total gross unrealized losses + References No definition available. + Details
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- Definition Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 + Details
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