Reinsurance (Reinsurance Recoverable by Counterparty) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 48,367,096	$ 40,710,159
PAR U
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	13,352,845	12,380,683
PALAC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	15,941,123	11,635,405
PURC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	5,368,831	4,692,769
PARCC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,572,428	2,627,595
GUL Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,573,609	2,292,638
PAR Term
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,913,265	1,825,594
Prudential Insurance
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,421,226	1,764,512
Prudential of Taiwan
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,649,998	1,499,685
Term Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,766,978	1,506,366
DART
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	502,770	327,235
Unaffiliated
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 304,023	$ 157,677