Income Taxes (Reconciliation To Effective Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%	35.00%
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Expected federal income tax expense (benefit)	$ 87,361	$ (609,393)	$ 14,308
Non-taxable investment income	(46,426)	(48,662)	(46,836)
Tax credits	(47,544)	(36,806)	(27,980)
Changes in tax law	0	(3,644)	(70,121)
Other	5,727	7,066	381
Total income tax expense (benefit) on income (loss) before equity in earnings of operating joint ventures	$ (882)	$ (691,439)	$ (130,248)
Effective tax rate	(0.20%)	23.80%	(191.20%)