Derivative Instruments (Financial Statement Classification and Impact of Derivatives Used in Qualifying and Non-qualifying Hedge Relationships) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, Net	$ 8,556
Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	11,538		(977)
Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	93		(12)
Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	237		15
Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	8,324	[1]	637	[1]
Cash Flow Hedging [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Cash Flow Hedging [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	93		(12)
Cash Flow Hedging [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	138		(3)
Cash Flow Hedging [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	8,324	[1]	637	[1]
Cash Flow Hedging [Member] | Cross Currency Interest Rate Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Cash Flow Hedging [Member] | Cross Currency Interest Rate Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	93		(12)
Cash Flow Hedging [Member] | Cross Currency Interest Rate Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	138		(3)
Cash Flow Hedging [Member] | Cross Currency Interest Rate Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	8,324	[1]	637	[1]
Nondesignated [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	11,538		(977)
Nondesignated [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	99		18
Nondesignated [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]
Nondesignated [Member] | Interest Rate Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	30,044		37,588
Nondesignated [Member] | Interest Rate Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Interest Rate Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Interest Rate Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]
Nondesignated [Member] | Cross Currency Interest Rate Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	6,006		824
Nondesignated [Member] | Cross Currency Interest Rate Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Cross Currency Interest Rate Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	99		18
Nondesignated [Member] | Cross Currency Interest Rate Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]
Nondesignated [Member] | Credit Risk Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(1)		(7)
Nondesignated [Member] | Credit Risk Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Credit Risk Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Credit Risk Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]
Nondesignated [Member] | Equity Contract [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(3,883)		(4,648)
Nondesignated [Member] | Equity Contract [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Equity Contract [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Equity Contract [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0	[1]	0	[1]
Nondesignated [Member] | Embedded Derivative [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(20,628)		(34,734)
Nondesignated [Member] | Embedded Derivative [Member] | Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Embedded Derivative [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		0
Nondesignated [Member] | Embedded Derivative [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	$ 0	[1]	$ 0	[1]

[1] (1) Amounts deferred in “Accumulated other comprehensive income (loss)”