Investments (Summary Of Components Of Net Realized Capital Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Schedule of Available-for-sale Securities [Line Items]
Credit allowances on fixed maturity securities	$ 1,500	$ (15,075)	$ (149)	$ (22,217)
Total net gains (losses) on investments	(378,273)	183,763	(604,860)	318,774
Beginning Balance	(29,140)	(8,708)	(27,491)	(1,566)
Credit losses on securities where credit losses were not previously recorded	(5,060)	(13,726)	(7,958)	(21,024)
Increases in allowance on previously impaired securities	(760)	(1,468)	(760)	(1,468)
Decrease in allowance on previously impaired securities
Reduction in allowance due to disposals	7,686	119	8,935	275
Ending Balance	(27,274)	(23,783)	(27,274)	(23,783)
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Beginning Balance			(27,491)
Ending Balance	(27,274)		(27,274)
Fixed Maturity Securities [Member] | Market Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Credit allowances on fixed maturity securities	1,500	(15,075)	(149)	(22,217)
Net realized gains (losses) from dispositions	(9,875)	4,128	(14,964)	8,055
Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Beginning Balance	(20,049)	(3,588)	(19,267)	(1,205)
Credit losses on securities where credit losses were not previously recorded	(4,888)	(13,538)	(6,817)	(15,921)
Increases in allowance on previously impaired securities	(653)	(1,468)	(653)	(1,468)
Decrease in allowance on previously impaired securities
Reduction in allowance due to disposals	6	119	1,153	119
Ending Balance	(25,584)	(18,475)	(25,584)	(18,475)
Asset Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Beginning Balance	(7,680)	(4,915)	(7,680)
Credit losses on securities where credit losses were not previously recorded				(4,915)
Increases in allowance on previously impaired securities
Decrease in allowance on previously impaired securities
Reduction in allowance due to disposals	7,680		7,680
Ending Balance		(4,915)		(4,915)
Equity Securities [Member] | Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Net realized gains (losses) from dispositions	(30,009)	585	(38,277)	6,823
Gains (losses) from fair value adjustments	(185,865)	103,824	(316,667)	141,375
Other Invested Assets [Member]
Schedule of Available-for-sale Securities [Line Items]
Other invested assets	583	2,748	4,502	4,094
Other Invested Assets [Member] | Fair Value [Member]
Schedule of Available-for-sale Securities [Line Items]
Gains (losses) from fair value adjustments	(154,658)	87,552	(239,277)	180,630
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Net realized gains (losses) from dispositions	51	1	(28)	14
Obligation of U.S. States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Beginning Balance	(151)		(151)
Credit losses on securities where credit losses were not previously recorded
Increases in allowance on previously impaired securities
Decrease in allowance on previously impaired securities
Reduction in allowance due to disposals
Ending Balance	(151)		(151)
Foreign Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Beginning Balance
Ending Balance
Foreign Corporate Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Beginning Balance	(1,260)	(205)	(393)	(361)
Credit losses on securities where credit losses were not previously recorded	(172)	(188)	(1,141)	(188)
Increases in allowance on previously impaired securities	(107)		(107)
Decrease in allowance on previously impaired securities
Reduction in allowance due to disposals			102	156
Ending Balance	$ (1,539)	$ (393)	$ (1,539)	$ (393)