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, 2013		Mar. 31, 2012
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, Net	$ 1,717
Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(40,825)		(42,595)
Net Investment Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(34)		(41)
Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	0		(10)
Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, Net	1,746	[1]	(1,201)	[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	(34)		(41)
Cash Flow Hedging [Member] | Other Income [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	5		2
Cash Flow Hedging [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, Net	1,746	[1]	(1,201)	[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	(34)		(41)
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	5		2
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 Other Comprehensive Income, Effective Portion, Net	1,746	[1]	(1,201)	[1]
Nondesignated [Member] | Net Realized Investments Gain Loss [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments Gain (Loss) Recognized In Income Net	(40,825)		(42,595)
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	(5)		(12)
Nondesignated [Member] | Accumulated Other Comprehensive Income (loss) [Member]
Derivative Instruments Gain Loss [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion, 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	(25,836)		(21,375)
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 Other Comprehensive Income, Effective Portion, 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	1,310		(1,155)
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	(5)		(12)
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 Other Comprehensive Income, Effective Portion, 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	(37)		98
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 Other Comprehensive Income, Effective Portion, 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	(30,451)		(32,837)
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 Other Comprehensive Income, Effective Portion, 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	14,189		12,674
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 Other Comprehensive Income, Effective Portion, Net	$ 0	[1]	$ 0	[1]

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