Reinsurance (Reinsurance Recoverable by Counterparty) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 40,710,159	$ 34,682,127
PAR U
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	12,380,683	11,444,032
PALAC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	11,635,405	8,828,190
PURC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	4,692,769	4,127,455
PARCC
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,627,595	2,527,690
GUL Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	2,292,638	2,017,810
PAR Term
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,825,594	1,678,745
Prudential Insurance
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,764,512	1,226,917
Prudential of Taiwan
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,499,685	1,414,669
Term Re
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	1,506,366	1,259,141
DART
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	327,235	119,946
Unaffiliated
Effects of Reinsurance [Line Items]
Total reinsurance recoverables	$ 157,677	$ 37,532