Investments (Realized Investment Gains Losses, Net) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022		Dec. 31, 2021
Schedule of Gain (Loss) on Investments [Line Items]
Realized investment gains (losses), net	$ (1,083,660)	$ 336,382	[1]	$ (386,894)	[2]
Fixed maturities
Schedule of Gain (Loss) on Investments [Line Items]
Realized investment gains (losses), net	(31,193)	(74,005)		(3,514)
Commercial mortgage and other loans
Schedule of Gain (Loss) on Investments [Line Items]
Realized investment gains (losses), net	(17,854)	(18,201)		1,535
Other invested assets
Schedule of Gain (Loss) on Investments [Line Items]
Realized investment gains (losses), net	36,246	(78,671)		(2,737)
Derivatives
Schedule of Gain (Loss) on Investments [Line Items]
Realized investment gains (losses), net	(1,072,892)	507,313		(382,531)
Short-term investments and cash equivalents
Schedule of Gain (Loss) on Investments [Line Items]
Realized investment gains (losses), net	$ 2,033	$ (54)		$ 353

[1] Prior period amounts reflect the implementation of ASU 2018-12: Targeted Improvements to the Accounting for Long-Duration Contracts.

[2] Prior period amounts reflect the implementation of ASU 2018-12: Targeted Improvements to the Accounting for Long-Duration Contracts.