Net Investment Gains (Losses) (Net Investment Gains (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Fixed maturity securities, gains	$ 1,705	$ 8,240
Fixed maturity securities, losses	(2,984)	(2,071)
Net realized gains on investment sales	905	8,572
Change in unrealized gains (losses)	93,213	(24,335)
Investment funds	(2,162)	47,671
Real estate (2)	286,192	12,909
Loans receivable	(32)	0
Other	(6,955)	773
Net realized and unrealized gains on investments in earnings before allowance for expected credit losses	369,882	51,759
Fixed maturity securities	(3,906)	(18,159)
Loans receivable	289	1,239
Change in allowance for expected credit losses on investments	(3,617)	(16,920)
Net investment gains	366,265	34,839
Income tax expense	(78,442)	(5,887)
After-tax net investment gains	$ 287,823	$ 28,952