Statements of Comprehensive Income (Loss) Statements of Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period					$ 189,391
Other comprehensive income (loss)	75,035		(218,402)		144,545		(255,401)
Accumulated Other Comprehensive Income (Loss), End of Period	333,899				333,899
Net investment gains	109,168		33,058		161,922		53,027
Income before income taxes	263,454		158,706		511,039		318,929
Income before taxes	534,150		494,286		1,049,316		975,890
Tax effect	(83,277)		(43,579)		(161,178)		(87,204)
After-tax amounts reclassified	180,177		115,127		349,861		231,725
Unrealized investment gains, pre-tax	76,390		(303,169)		188,680		(291,154)
Unrealized investment gains, tax effect	(28,190)		106,109		(67,536)		101,904
Unrealized investment gains, after-tax amounts	48,200		(197,060)		121,144		(189,250)
Currency translation adjustment, pre-tax	24,815		(23,156)		20,790		(69,779)
Currency translation adjustment, tax effect	0		0		0		0
Change in unrealized currency translation adjustments	24,815		(23,156)		20,790		(69,779)
Net pension asset, pre-tax	3,108		2,790		4,017		5,582
Net pension asset, tax effect	(1,088)		(976)		(1,406)		(1,954)
Net pension asset, after-tax amounts	2,020		1,814		2,611		3,628
Other comprehensive income (loss), pre-tax	104,313		(323,535)		213,487		(355,351)
Other comprehensive income (loss), tax effect	(29,278)		105,133		(68,942)		99,950
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period	329,492		525,428		256,566		517,658
Other comprehensive income (loss) before reclassifications	62,846		(182,934)		140,289		(161,945)
Amounts reclassified from AOCI	(14,646)		(14,126)		(19,145)		(27,305)
Other comprehensive income (loss)	48,200		(197,060)		121,144		(189,250)
Unrealized investment gain related to non-controlling interest	(19)		35		(37)		(5)
Accumulated Other Comprehensive Income (Loss), End of Period	377,673		328,403		377,673		328,403
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period	(64,549)		(83,299)		(60,524)		(36,676)
Other comprehensive income (loss) before reclassifications	24,815		(23,156)		20,790		(69,779)
Amounts reclassified from AOCI	0		0		0		0
Other comprehensive income (loss)	24,815		(23,156)		20,790		(69,779)
Unrealized investment gain related to non-controlling interest	0				0
Accumulated Other Comprehensive Income (Loss), End of Period	(39,734)		(106,455)		(39,734)		(106,455)
Change in unrealized currency translation adjustments					20,790		(69,779)
Net Pension Asset [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period	(6,060)		(13,537)		(6,651)		(15,351)
Other comprehensive income (loss) before reclassifications	0		0		0		0
Amounts reclassified from AOCI	2,020		1,814		2,611		3,628
Other comprehensive income (loss)	2,020		1,814		2,611		3,628
Unrealized investment gain related to non-controlling interest	0				0
Accumulated Other Comprehensive Income (Loss), End of Period	(4,040)		(11,723)		(4,040)		(11,723)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning of Period	258,883		428,592		189,391		465,631
Other comprehensive income (loss) before reclassifications	87,661		(206,090)		161,079		(231,724)
Amounts reclassified from AOCI	(12,626)		(12,312)		(16,534)		(23,677)
Other comprehensive income (loss)	75,035		(218,402)		144,545		(255,401)
Unrealized investment gain related to non-controlling interest	(19)		35		(37)		(5)
Accumulated Other Comprehensive Income (Loss), End of Period	333,899		210,225		333,899		210,225
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net investment gains	(22,532)	[1]	(21,933)		(29,454)	[1]	(42,008)	[1]
Tax effect	7,886	[2]	7,807	[2]	10,309	[2]	14,703	[2]
After-tax amounts reclassified	(14,646)		(14,126)		(19,145)		(27,305)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Income before income taxes	0		0		0		0
Tax effect	0	[2]	0	[2]	0	[2]	0	[2]
After-tax amounts reclassified	0		0		0		0
Reclassification out of Accumulated Other Comprehensive Income [Member] | Net Pension Asset [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Income before taxes	3,108	[3]	2,790		4,017	[3]	5,582	[3]
Tax effect	(1,088)	[2]	(976)	[2]	(1,406)	[2]	(1,954)	[2]
After-tax amounts reclassified	2,020		1,814		2,611		3,628
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Income before income taxes	(19,424)		(19,143)		(25,437)		(36,426)
Tax effect	6,798	[2]	6,831	[2]	8,903	[2]	12,749	[2]
After-tax amounts reclassified	$ (12,626)		$ (12,312)		$ (16,534)		$ (23,677)

[1] Net investment gains in the consolidated statements of operations.

[2] Income tax expense in the consolidated statements of operations.

[3] Other operating costs and expenses in the consolidated statements of operations.