Derivative Instruments (Gross Notional Amount and Fair Value of Derivatives Contracts) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Notional	$ 57,509,543	$ 43,902,689
Assets	226,570	243,118
Liabilities	(71,526)	(58,687)
FV Of Embedded Derivatives Included In Future Policy Benefits	3,117,000	4,994,000
UPARC Embedded Derivative	245,000	376,000
Gross Asset Amount
Derivative [Line Items]
FV Of Embedded Derivatives Included In Reinsurance Recoverable	2,778,000	4,522,000
Derivatives Designated as Hedge Accounting Instruments:
Derivative [Line Items]
Notional	358,065	291,100
Assets	28,365	14,733
Liabilities	(3,829)	(3,008)
Derivatives Designated as Hedge Accounting Instruments: | Foreign Currency Swaps
Derivative [Line Items]
Notional	358,065	291,100
Assets	28,365	14,733
Liabilities	(3,829)	(3,008)
Derivatives Not Qualifying as Hedge Accounting Instruments:
Derivative [Line Items]
Notional	57,151,478	43,611,589
Assets	198,205	228,385
Liabilities	(67,697)	(55,679)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Foreign Currency Swaps
Derivative [Line Items]
Notional	155,246	101,653
Assets	10,847	6,677
Liabilities	(1,074)	(712)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate Swaps
Derivative [Line Items]
Notional	3,184,400	3,184,400
Assets	147,160	192,181
Liabilities	(49,507)	(20,574)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Foreign Currency Forwards
Derivative [Line Items]
Notional	22,919	1,025
Assets	5	40
Liabilities	(129)	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit Default Swaps
Derivative [Line Items]
Notional	7,275	12,275
Assets	112	150
Liabilities	(417)	(513)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Total Return Swaps
Derivative [Line Items]
Notional	567,668	577,054
Assets	9,067	2,405
Liabilities	0	(19,670)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity Options
Derivative [Line Items]
Notional	53,213,970	39,735,182
Assets	31,014	26,932
Liabilities	$ (16,570)	$ (14,210)