Reinsurance (Reinsurance amounts included in the Statements of Financial Position) (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2023
Effects of Reinsurance [Line Items]
Reinsurance recoverables and deposit receivables	$ 49,168,211	$ 48,247,817
Policy loans	(1,556,658)	(1,541,480)
Deferred policy acquisition costs	(8,004,461)	(7,807,060)	$ (7,301,185)	$ (7,144,736)
Deferred sales inducements	(316,062)	(322,351)
Market risk benefit assets	2,508,967	2,637,363	2,537,000
Other assets	1,803,131	1,850,800
Future policy benefits	25,543,127	25,113,767	23,412,117
Market risk benefit liabilities	4,803,284	4,281,244	$ 4,388,000
Other liabilities	4,221,908	4,199,803
Impacts of Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables and deposit receivables	49,168,211	48,247,817
Policy loans	(1,144,906)	(1,143,726)
Deferred policy acquisition costs	(3,286,351)	(3,319,067)
Deferred sales inducements	(31,971)	(32,573)
Market risk benefit assets	1,253,961	1,145,580
Other assets	1,511,709	1,538,231
Policyholders’ account balances	5,452,802	5,567,661
Future policy benefits	7,597,732	7,443,997
Market risk benefit liabilities	256,287	302,310
Reinsurance and funds withheld payables	8,889,142	8,611,141
Other liabilities	3,250,307	3,282,713
Unaffiliated activity
Effects of Reinsurance [Line Items]
Market risk benefit assets	861,899	804,015
Other assets	1,102,141	1,118,974
Policyholders’ account balances	1,623,421	1,665,998
Future policy benefits	267	160
Market risk benefit liabilities	128,112	151,432
Reinsurance and funds withheld payables	3,344,608	3,360,901
Other liabilities	250,850	257,929
Unaffiliated activity
Effects of Reinsurance [Line Items]
Policy loans	(48,960)	(48,644)
Deferred policy acquisition costs	$ (635,819)	$ (637,555)