Investments (Realized Investment Gains Losses, Net) (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024		Jun. 30, 2025	Jun. 30, 2024
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	$ (819,364)	$ 804,748	[1]	$ (925,738)	$ 801,943	[1]
Fixed maturities
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	(4,178)	(8,631)		(16,122)	(15,468)
Commercial mortgage and other loans
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	(3,828)	1,162		(6,425)	(4,619)
LPs/LLCs
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	0	(36)		(6)	(36)
Derivatives
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	(774,743)	794,315		(824,602)	788,964
Short-term investments and cash equivalents
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	116	267		33	(80)
Ceded income on modified coinsurance investments
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	(36,799)	17,671		(78,802)	33,017
Other
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	$ 68	$ 0		$ 186	$ 165

[1] Amounts reflect revision to prior period Financial Statements. See Note 17 for additional information.