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Investments (Aggregated Income Statement Summarized Financial Information for Partnerhips in our Alternative Investment Portfolio) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Net investment income earned	$ 69,716	$ 55,967
Carrying Value	290,153		$ 266,322
Alternative Investments [Member]
Schedule of Equity Method Investments [Line Items]
Net investment income earned	20,200	6,300
Investments accounted for under the equity method [Member]
Schedule of Equity Method Investments [Line Items]
Net investment income	481,600	12,700
Realized gains	776,000	164,800
Net change in unrealized appreciation	4,630,800	1,204,000
Insurance Subsidiaries' alternative investments income	$ 5,888,400	$ 1,381,500

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The amount of net income (loss) reported by an equity method investment of the entity.

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Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(2))
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Amount of investments classified as other.

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-Topic 944
-SubTopic 210
-Section S99
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