Net Investment Gains (Losses) (Change in Unrealized Gains (Losses) of Available For Sales Securities) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	$ 28,804	$ 395,624	$ (84,931)	$ 62,777
Income tax (expense) benefit	(5,532)	(76,899)	18,073	(3,034)
Noncontrolling interests	(1)	(1)	(1)	1
Total change in unrealized gains	23,271	318,724	(66,859)	59,744
Debt securities
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	28,511	369,615	(94,058)	43,199
Fixed maturity securities with allowance for expected credit losses
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	(69)	23,450	10,286	24,991
Investment funds
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	762	4,212	(257)	(3,434)
Other
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	$ (400)	$ (1,653)	$ (902)	$ (1,979)