Investments (Fixed Maturities Securities Proceeds) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Proceeds from maturities/prepayments	$ 4,240,000	$ 1,736,809	$ 1,688,079
Fixed maturities | Available-for-sale
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales	2,097,519	460,596	1,117,293
Proceeds from maturities/prepayments	2,300,919	1,218,844	624,640
Gross investment gains from sales and maturities	23,978	11,482	5,647
Gross investment losses from sales and maturities	(143,432)	(43,078)	(58,432)
Write-downs recognized in earnings	(9,534)	(2,358)	(20,600)
(Addition to) release of allowance for credit losses	(38,406)	2,761	(620)
Noncash or part noncash divestiture, amount of consideration received	$ (158,400)	$ 57,400	$ (53,900)