Investments (Summary Of Aggregate Market Value And Gross Unrealized Depreciation Of Fixed Maturity And Equity Securities, By Contractual Maturity) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	$ 10,388,190	$ 5,390,316
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(763,375)	(70,899)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	937,217	491,820
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(121,840)	(15,230)
Fixed maturity securities, Duration of Unrealized Loss, Total, Fair Value	11,325,407	5,882,136
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation	(885,215)	(86,129)
No Recorded Allowance for Credit Losses [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	10,381,136
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(762,520)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	937,217
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(121,840)
Fixed maturity securities, Duration of Unrealized Loss, Total, Fair Value	11,318,353
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation	(884,360)
Due In One Year Or Less [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	342,251	81,412
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(2,566)	(1,878)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	39,994	35,515
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(3,187)	(3,829)
Fixed maturity securities, Duration of Unrealized Loss, Total, Fair Value	382,245	116,927
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation	(5,753)	(5,707)
Due In One Year Through Five Years [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	2,518,832	1,209,378
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(149,344)	(18,614)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	315,227	154,449
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(23,856)	(3,418)
Fixed maturity securities, Duration of Unrealized Loss, Total, Fair Value	2,834,059	1,363,827
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation	(173,200)	(22,032)
Due In Five Years Through Ten Years [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	1,401,318	852,857
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(158,998)	(20,678)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	248,982	34,164
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(46,474)	(1,977)
Fixed maturity securities, Duration of Unrealized Loss, Total, Fair Value	1,650,300	887,021
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation	(205,472)	(22,655)
Due After Ten Years [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	951,123	516,562
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(155,708)	(9,666)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	48,557	26,736
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(11,837)	(888)
Fixed maturity securities, Duration of Unrealized Loss, Total, Fair Value	999,680	543,298
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation	(167,545)	(10,554)
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	3,518,224	1,890,876
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(177,153)	(10,713)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	9,307	37,910
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(737)	(301)
Fixed maturity securities, Duration of Unrealized Loss, Total, Fair Value	3,527,531	1,928,786
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation	(177,890)	(11,014)
Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	1,649,388	839,231
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(118,751)	(9,350)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value	275,150	203,046
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation	(35,749)	(4,817)
Fixed maturity securities, Duration of Unrealized Loss, Total, Fair Value	1,924,538	1,042,277
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation	(154,500)	(14,167)
Recorded An Allowance For Credit Losses [Member]
Schedule of Available-for-sale Securities [Line Items]
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Market Value	7,054
Fixed maturity securities, Duration of Unrealized Loss, Less than 12 months, Gross Unrealized Depreciation	(855)
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Market Value
Fixed maturity securities, Duration of Unrealized Loss, Greater than 12 months, Gross Unrealized Depreciation
Fixed maturity securities, Duration of Unrealized Loss, Total, Fair Value	7,054	15,700
Fixed maturity securities, Duration of Unrealized Loss, Total, Gross Unrealized Depreciation	$ (855)	$ (400)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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