Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 794,772	$ 603,607	$ 1,559,938	$ 1,135,670
Less: investment expenses	(31,519)	(23,614)	(61,889)	(50,357)
Net investment income	763,253	579,993	1,498,049	1,085,313
Equity securities
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	12,184	6,458	30,768	10,205
Commercial mortgage and other loans
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	102,557	77,920	199,804	151,678
Policy loans
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	16,813	16,588	33,029	31,033
Other invested assets
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	54,306	28,747	118,185	52,067
Short-term investments and cash equivalents
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	25,085	41,007	59,922	87,322
Available-for-sale | Fixed maturities
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	533,845	393,930	1,021,045	732,739
Trading | Fixed maturities
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 49,982	$ 38,957	$ 97,185	$ 70,626