Reinsurance (Reinsurance Recoverable by Counterparty) (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	$ 49,168,211	$ 48,247,817
PAR U
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	11,415,651	11,426,975
PURE
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	7,962,181	7,951,965
Prudential Insurance
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	7,874,836	7,507,414
PARCC
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	7,042,276	7,049,164
Lotus Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	2,524,184	2,130,095
Prudential of Japan
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	10,841	0
Unaffiliated activity
Effects of Reinsurance [Line Items]
Total reinsurance recoverable and deposit receivables	$ 12,338,242	$ 12,182,204