Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net income	$ 145,386	$ 132,412	$ 394,144	$ 396,191
Unrealized gains (losses) on securities:
Less applicable (taxes) benefits	28,690	1,478	265,555	(362,872)
Unrealized investment gains (losses), net of tax	(52,927)	(2,702)	(493,227)	674,117
Unrealized gains (losses) attributable to deferred acquisition costs	1,436	693	5,041	(6,580)
Less applicable (taxes) benefits	(502)	(243)	(1,764)	2,303
Unrealized gains (losses) attributable to deferred acquisition costs, net of tax	934	450	3,277	(4,277)
Foreign exchange translation adjustments, other than securities	(9,031)	(6,650)	(22,567)	(4,642)
Less applicable (taxes) benefits	3,164	2,084	7,667	1,334
Foreign exchange translation adjustments, other than securities, net of tax	(5,867)	(4,566)	(14,900)	(3,308)
Pension adjustments	3,646	2,571	11,118	8,176
Less applicable (taxes) benefits	(1,276)	(900)	(3,891)	(2,862)
Pension adjustments, net of tax	2,370	1,671	7,227	5,314
Other comprehensive income (loss)	(55,490)	(5,147)	(497,623)	671,846
Comprehensive income (loss)	89,896	127,265	(103,479)	1,068,037
Securities [Member]
Unrealized gains (losses) on securities:
Unrealized holding gains (losses) arising during period	(72,228)	(2,627)	(740,934)	1,057,710
Reclassification adjustment for (gains) losses on securities included in net income	(5,540)	1,261	(7,138)	(15,935)
Reclassification adjustment for amortization of (discount) and premium	(1,569)	(2,354)	(4,840)	(6,898)
Foreign exchange adjustment on securities recorded at fair value	(1,217)	(523)	(2,480)	(654)
Unrealized gains (losses) on securities	(80,554)	(4,243)	(755,392)	1,034,223
Other Investments [Member]
Unrealized gains (losses) on securities:
Unrealized gains (losses) on other investments	(1,063)	63	(3,390)	2,766
Total unrealized investment gains (losses)	$ (81,617)	$ (4,180)	$ (758,782)	$ 1,036,989