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v3.20.4

Segment Reporting (Narrative) (Details) | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Segment Reporting [Abstract] |  |  |
Percentage threshold of Company revenue not exceeded by any other country | 20.10% | 23.10% | 19.70%

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- References No definition available. + Details
Name: | re_PercentageThresholdOfCompanyRevenueNotExceededByAnyOtherCountry
Namespace Prefix: | re_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- References No definition available. + Details
Name: | us-gaap_SegmentReportingAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration