Reinsurance (Narrative) (Details) - USD ($) $ in Thousands								6 Months Ended	21 Months Ended	36 Months Ended		48 Months Ended
	Jan. 01, 2018	Jan. 01, 2017	Dec. 31, 2013	Jul. 01, 2012	Dec. 31, 2010	Dec. 31, 2009	Jan. 31, 2001	Jun. 30, 2019	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2013	Dec. 31, 2017	Dec. 31, 2013	Dec. 31, 2018
Effects of Reinsurance [Line Items]
Reinsurance recoverables								$ 38,946,785						$ 34,682,127
PAR U
Effects of Reinsurance [Line Items]
Reinsurance recoverables								11,963,017						11,444,032
PURC
Effects of Reinsurance [Line Items]
Reinsurance recoverables								4,371,948						4,127,455
PARCC
Effects of Reinsurance [Line Items]
Reinsurance recoverables								2,480,256						2,527,690
GUL Re
Effects of Reinsurance [Line Items]
Reinsurance recoverables								2,110,403						2,017,810
PAR Term
Effects of Reinsurance [Line Items]
Reinsurance recoverables								1,726,036						1,678,745
Prudential of Taiwan
Effects of Reinsurance [Line Items]
Reinsurance recoverables								1,426,279						1,414,669
Term Re
Effects of Reinsurance [Line Items]
Reinsurance recoverables								1,417,733						1,259,141
Prudential Insurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables								1,624,532						1,226,917
DART
Effects of Reinsurance [Line Items]
Reinsurance recoverables								220,163						$ 119,946
Union Hamilton Reinsurance, Ltd.
Effects of Reinsurance [Line Items]
Reinsurance recoverables								$ 3,100,000
Union Hamilton Reinsurance, Ltd. | Quote Share Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance Retention Policy, Reinsured Risk, Percentage									50.00%
Affiliated Entity | PAR U
Effects of Reinsurance [Line Items]
Reinsurance Retention Policy, Reinsured Risk, Percentage				95.00%	70.00%
Affiliated Entity | PURC
Effects of Reinsurance [Line Items]
Reinsurance Retention Policy, Reinsured Risk, Percentage										95.00%	70.00%
Affiliated Entity | PARCC
Effects of Reinsurance [Line Items]
Reinsurance Retention Policy, Reinsured Risk, Percentage						90.00%
Affiliated Entity | GUL Re
Effects of Reinsurance [Line Items]
Reinsurance Retention Policy, Reinsured Risk, Percentage		95.00%	30.00%
Affiliated Entity | PAR Term
Effects of Reinsurance [Line Items]
Reinsurance Retention Policy, Reinsured Risk, Percentage													95.00%
Affiliated Entity | Prudential of Taiwan
Effects of Reinsurance [Line Items]
Related Party Transaction, Term							2 years
Affiliated Entity | Term Re
Effects of Reinsurance [Line Items]
Reinsurance Retention Policy, Reinsured Risk, Percentage												95.00%
Affiliated Entity | Prudential Insurance
Effects of Reinsurance [Line Items]
Reinsurance Retention Policy, Reinsured Risk, Percentage								100.00%
Affiliated Entity | DART
Effects of Reinsurance [Line Items]
Reinsurance Retention Policy, Reinsured Risk, Percentage	95.00%