Net Investment Gains (Losses) (Change in Unrealized Gains (Losses) of Available For Sales Securities) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment losses	$ (113,735)	$ (332,850)
Income tax benefit	23,605	73,869
Noncontrolling interests	0	1
Total change in unrealized gains	(90,130)	(258,980)
Debt securities
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment losses	(122,568)	(326,416)
Fixed maturity securities with allowance for expected credit losses
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment losses	10,355	1,541
Investment funds
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment losses	(1,020)	(7,646)
Other
Realized and Unrealized Investment Gains Losses [Line Items]
Total change in unrealized investment losses	$ (502)	$ (329)