Reinsurance (Reinsurance amounts included in the Statements of Financial Position) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Effects of Reinsurance [Line Items]
Reinsurance recoverables	$ 43,285,050	$ 38,709,651
Policy loans	(1,524,636)	(1,472,677)
Deferred policy acquisition costs	(7,706,078)	(7,097,511)	$ (6,923,554)	$ (6,930,425)
Deferred sales inducements	(330,264)	(351,424)
Market risk benefits assets	2,499,234	2,367,243	2,519,000
Other assets	2,934,252	2,078,938
Future policy benefits	25,253,059	23,205,205	21,257,134
Market risk benefit liabilities	4,915,163	5,144,401	$ 4,371,000
Other liabilities	9,683,019	5,170,308
Impacts of Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables	43,285,050	38,709,651
Policy loans	(1,107,607)	(1,082,584)
Deferred policy acquisition costs	(3,118,226)	(3,195,161)
Deferred sales inducements	(33,303)	(35,313)
Market risk benefits assets	1,212,865	1,165,378
Other assets	2,778,500	1,897,410
Policyholders’ account balances	5,646,936	5,977,108
Future policy benefits	7,431,811	7,026,209
Market risk benefit liabilities	263,588	249,538
Other liabilities	8,920,647	4,397,862
Unaffiliated activity
Effects of Reinsurance [Line Items]
Market risk benefits assets	814,183	745,662
Other assets	2,680,090	1,795,422
Policyholders’ account balances	1,684,769	1,830,579
Future policy benefits	194	453
Market risk benefit liabilities	134,758	131,594
Other liabilities	2,798,751	1,915,205
Unaffiliated activity
Effects of Reinsurance [Line Items]
Deferred policy acquisition costs	$ 62,301	$ 71,315