Derivative Instruments (Gross Notional Amount and Fair Value of Derivatives Contracts) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Notional	$ 26,055,095	$ 29,709,613
Assets	86,623	300,655
Liabilities	(10,405)	(32,849)
Future Policy Benefits
Derivative [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset (Liability), Net	(8,657,000)	(5,205,000)
Reinsurance Recoverables
Derivative [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset (Liability), Net	9,142,000	4,940,000
Reinsurance Recoverables | Affiliated Entity
Derivative [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset (Liability), Net	8,595,000	4,593,000
Reinsurance Recoverables | UPARC
Derivative [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset (Liability), Net	485,000	340,000
Reinsurance Recoverables | Union Hamilton Reinsurance, Ltd.
Derivative [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset (Liability), Net	62,000	7,000
Derivatives Designated as Hedge Accounting Instruments:
Derivative [Line Items]
Notional	401,047	529,128
Assets	40,453	50,877
Liabilities	(2,588)	(1,385)
Derivatives Designated as Hedge Accounting Instruments: | Foreign Currency Swaps
Derivative [Line Items]
Notional	401,047	529,128
Assets	40,453	50,877
Liabilities	(2,588)	(1,385)
Derivatives Not Qualifying as Hedge Accounting Instruments:
Derivative [Line Items]
Notional	25,654,048	29,180,485
Assets	46,170	249,778
Liabilities	(7,817)	(31,464)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Foreign Currency Swaps
Derivative [Line Items]
Notional	57,209	122,425
Assets	8,751	17,079
Liabilities	(133)	(71)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate Swaps
Derivative [Line Items]
Notional	101,075	3,159,400
Assets	15,119	203,313
Liabilities	(103)	(8,605)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Foreign Currency Forwards
Derivative [Line Items]
Notional	19,482	3,722
Assets	1,004	39
Liabilities	0	(15)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit Default Swaps
Derivative [Line Items]
Notional	7,275	7,275
Assets	71	268
Liabilities	(294)	(222)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Total Return Swaps
Derivative [Line Items]
Notional	0	542,294
Assets	0	411
Liabilities	0	(10,451)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity Options
Derivative [Line Items]
Notional	25,469,007	25,345,369
Assets	21,225	28,668
Liabilities	$ (7,287)	$ (12,100)