Investments (Realized Investment Gains Losses, Net) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	$ (616,495)	$ (468,256)	$ 245,387	$ (581,241)
Fixed maturities
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	(26,993)	(8,931)	(42,461)	(17,154)
Commercial mortgage and other loans
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	(3,533)	(5,059)	(8,152)	(7,143)
Other invested assets
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	(36,941)	10,856	(3,795)	24,052
Derivatives
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	(549,017)	(465,176)	299,886	(582,846)
Short-term investments and cash equivalents
Schedule Of Gain Loss On Investments [Line Items]
Realized Investment gains (losses), net	$ (11)	$ 54	$ (91)	$ 1,850