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Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2021
Significant Accounting Policies [Line Items]
Premium revenue recognition period	12 months
Securities lending rate of collateral required (percentage)	102.00%
Equity method investments, time lag for reporting - low end of range	1 month
Equity method investments, time lag for reporting - high end of range	3 months
Vesting period, share-based awards	3 years
Requisite service period, share-based awards	3 years
Losses occurring
Significant Accounting Policies [Line Items]
Premium revenue recognition period	12 months
Risks attaching
Significant Accounting Policies [Line Items]
Premium revenue recognition period	24 months

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- Definition

Equity Method Investments Time Lag For Reporting High End of Range

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-- None. No documentation exists for this element. --

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- Definition

The rate of collateral required, expressed as a percentage of the fair value of loaned securities.

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- Definition

[Line Items] for Significant Accounting Policies [Table]

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- Definition

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

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-Name Accounting Standards Codification
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