Reinsurance (Reinsurance Recoverable by Counterparty) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 36,860,011	$ 37,096,562	[1]
PAR U
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	15,272,691	15,051,337
PURC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	7,169,637	6,928,950
PARCC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,237,002	2,437,589
GUL Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	3,096,035	3,124,697
PAR Term
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,902,278	2,040,599
Prudential Insurance
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,112,606	986,013
Term Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,829,064	1,830,197
Lotus Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,034,218	1,952,215
DART
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	604,117	578,462
Unaffiliated
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 1,602,363	$ 2,166,503

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