Reinsurance (Reinsurance amounts included in the Statements of Financial Position) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Effects of Reinsurance [Line Items]
Reinsurance recoverables	$ 41,060,869	$ 38,709,651
Policy Loans	(1,496,241)	(1,472,677)
Deferred policy acquisition costs	(7,245,454)	(7,097,511)	$ (7,039,669)	$ (6,930,425)
Deferred sale inducement	(344,893)	(351,424)
Market risk benefits assets	2,536,843	2,367,243	1,427,000
Other Assets	2,347,175	2,078,938
Future policy benefits	23,362,318	23,205,205	21,759,543
Market risk benefit liabilities	4,388,317	5,144,401	$ 5,622,000
Other liabilities	8,361,698	5,170,308
Impacts of Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables	41,060,869	38,709,651
Policy Loans	(1,094,070)	(1,082,584)
Deferred policy acquisition costs	(3,190,663)	(3,195,161)
Deferred sale inducement	(34,683)	(35,313)
Market risk benefits assets	1,064,022	1,165,378
Other Assets	2,198,467	1,897,410
Policyholders’ account balances	5,901,708	5,977,108
Future policy benefits	7,109,698	7,026,209
Market risk benefit liabilities	302,169	249,538
Other liabilities	7,655,980	4,397,862
Unaffiliated activity
Effects of Reinsurance [Line Items]
Deferred policy acquisition costs	(68,424)	(71,315)
Market risk benefits assets	715,512	745,662
Other Assets	2,099,315	1,795,422
Policyholders’ account balances	1,817,895	1,830,579
Future policy benefits	130	453
Market risk benefit liabilities	157,687	131,594
Other liabilities	$ 2,179,341	$ 1,915,205