Reinsurance (Reinsurance Recoverable by Counterparty) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 39,356,117	$ 38,598,767
PAR U
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	13,216,951	13,523,832
PALAC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	6,967,660	7,198,504
PURC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	5,728,576	5,830,441
PARCC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,336,813	2,371,491
GUL Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,649,984	2,710,926
PAR Term
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,976,337	1,972,339
Prudential Insurance
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,616,373	2,082,551
Term Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,990,432	1,953,063
Lotus Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,963,819	32,039
DART
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	674,933	644,101
Unaffiliated
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 234,239	$ 279,480