CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Revenues
Premiums and policy fees	$ 2,799,390		$ 2,784,134	[1]	$ 2,609,357	[1]
Reinsurance ceded	(1,310,097)		(1,363,914)	[1]	(1,380,712)	[1]
Net of reinsurance ceded	1,489,293		1,420,220	[1]	1,228,645	[1]
Net investment income	1,789,338		1,753,444	[1]	1,624,845	[1]
Realized investment gains (losses):
Derivative financial instruments	(227,816)		(155,005)	[1]	(144,438)	[1]
All other investments	232,836		247,753	[1]	158,420	[1]
Other-than-temporary impairment losses	(67,130)		(62,210)	[1]	(74,970)	[1]
Portion recognized in other comprehensive income (before taxes)	8,986		14,889	[1]	33,606	[1]
Net impairment losses recognized in earnings	(58,144)		(47,321)	[1]	(41,364)	[1]
Other income	230,553		189,494	[1]	110,876	[1]
Total revenues	3,456,060		3,408,585	[1]	2,936,984	[1]
Benefits and expenses
Benefits and settlement expenses, net of reinsurance ceded: (2012 - $1,228,897; 2011 - $1,231,405; 2010 - $1,283,054)	2,317,121		2,222,220	[1]	2,076,392	[1]
Amortization of deferred policy acquisition costs and value of business acquired	192,183		249,520	[1]	144,496	[1]
Other operating expenses, net of reinsurance ceded: (2012 - $200,442; 2011 - $203,868; 2010 - $205,299)	487,177		461,570	[1]	382,920	[1]
Total benefits and expenses	2,996,481		2,933,310	[1]	2,603,808	[1]
Income before income tax	459,579		475,275	[1]	333,176	[1]
Income tax (benefit) expense
Current	81,006		(4,576)	[1]	6,544	[1]
Deferred	70,037		156,095	[1]	103,321	[1]
Total income tax expense	151,043		151,519	[1]	109,865	[1]
Net income	$ 308,536	[1]	$ 323,756	[1]	$ 223,311	[1]

[1] Recast from previously reported information