Derivative Instruments (Financial Statement Classification and Impact of Derivatives Used in Qualifying and Non-qualifying Hedge Relationships) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	$ 1,381	$ (8,113)	$ (194,055)
Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	608	14	(89)
Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	1,318	277	17
Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	10,008	8,492	(585)
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	608	14	(89)
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	1,116	134	(7)
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	10,008	8,492	(585)
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Currency/Interest Rate | Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Currency/Interest Rate | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	608	14	(89)
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Currency/Interest Rate | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	1,116	134	(7)
Derivatives Designated as Hedge Accounting Instruments: | Cash flow hedges | Currency/Interest Rate | Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	10,008	8,492	(585)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	1,381	(8,113)	(194,055)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	202	143	24
Derivatives Not Qualifying as Hedge Accounting Instruments: | Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate | Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	20,536	123,327	(116,025)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate | Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency | Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	115	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency | Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency/Interest Rate | Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	8,337	5,934	(204)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency/Interest Rate | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency/Interest Rate | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	202	143	24
Derivatives Not Qualifying as Hedge Accounting Instruments: | Currency/Interest Rate | Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit | Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(3)	(14)	(103)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit | Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity | Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(3,233)	(23,811)	(79,498)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity | Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Embedded Derivatives | Realized Investment Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(24,371)	(113,549)	1,775
Derivatives Not Qualifying as Hedge Accounting Instruments: | Embedded Derivatives | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Embedded Derivatives | Other Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Embedded Derivatives | Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	$ 0	$ 0	$ 0