Reinsurance (Reinsurance Recoverable by Counterparty) (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	$ 51,591,454	$ 48,247,817
PAR U
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	11,551,748	11,426,975
Prudential Insurance
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	8,606,854	7,507,414
PURE
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	8,117,172	7,951,965
PARCC
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	7,095,158	7,049,164
Lotus Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	3,242,925	2,130,095
Prudential of Japan
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	12,267	0
Unaffiliated
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	$ 12,965,330	$ 12,182,204