Equity (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022		Jun. 30, 2023	Jun. 30, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	[1]				$ (10,065)
Income tax benefit (expense)		$ 102,846	$ (27,805)	[2]	(7,416)	$ (45,818)	[2]
Ending Balance		19,748			19,748
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance					(20,007)	(11,274)
Change in OCI before reclassifications					3,266	(7,870)
Amounts reclassified from AOCI					0	0
Income tax benefit (expense)					(363)	735
Ending Balance		(17,104)	(18,409)		(17,104)	(18,409)
Net unrealized investment gains (losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance					(1,474,475)	306,331
Change in OCI before reclassifications					116,395	(1,824,967)
Amounts reclassified from AOCI					2,479	7,026
Income tax benefit (expense)					(24,884)	381,696
Ending Balance		(1,380,485)	(1,129,914)		(1,380,485)	(1,129,914)
Accumulated Other Comprehensive   Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance					(10,065)	396,454
Change in OCI before reclassifications					34,750	206,443
Amounts reclassified from AOCI					2,479	7,026
Income tax benefit (expense)					(7,416)	(45,818)
Ending Balance		19,748	564,105		19,748	564,105
Interest Rate Remeasurement of Future Policy Benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance					119,368	(125,809)
Change in OCI before reclassifications					(17,588)	249,694
Amounts reclassified from AOCI					0	0
Income tax benefit (expense)					3,693	(52,436)
Ending Balance		105,473	71,449		105,473	71,449
Gain (loss) from Changes in Non-Performance Risk on Market Risk Benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance					1,365,049	227,206
Change in OCI before reclassifications					(67,323)	1,789,586
Amounts reclassified from AOCI					0	0
Income tax benefit (expense)					14,138	(375,813)
Ending Balance		1,311,864	1,640,979		1,311,864	1,640,979
Cash flow hedges | Net unrealized investment gains (losses)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance					40,000	40,000
Ending Balance		$ 100,000	$ 144,000		$ 100,000	$ 144,000

[1] Prior period amounts adjusted for the implementation of Accounting Standard Update ("ASU") 2018-12: Targeted Improvements to the Accounting for Long-Duration Contracts.

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