Net Investment Gains (Losses) (Change in Unrealized Gains (Losses) of Available For Sales Securities) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	$ 48,980	$ (28,592)	$ 111,756	$ 287,739
Income tax (expense) benefit	(10,707)	3,847	(13,740)	(68,060)
Noncontrolling interests	(3)	123	(2)	105
Total change in unrealized gains	38,270	(24,622)	98,014	219,784
Debt securities
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	46,164	(12,178)	89,363	308,945
Fixed maturity securities with allowance for expected credit losses
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	5,036	384	30,027	396
Investment funds
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	(198)	(2,689)	(3,632)	4,863
Other
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment gains (losses)	$ (2,022)	$ (14,109)	$ (4,002)	$ (26,465)