CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Net premiums	$ 8,570,741	$ 8,669,854	$ 8,254,027
Investment income, net of related expenses	1,734,495	1,713,691	1,699,865
Investment related gains (losses), net:
Other-than-temporary impairments on fixed maturity securities	(57,380)	(7,766)	(12,654)
Other-than-temporary impairments on fixed maturity securities transferred to (from) accumulated other comprehensive income	0	0	(247)
Other investment related gains (losses), net	(107,370)	193,959	76,891
Total investment related gains (losses), net	(164,750)	186,193	63,990
Other revenues	277,692	334,456	300,471
Total revenues	10,418,178	10,904,194	10,318,353
Benefits and expenses
Claims and other policy benefits	7,489,382	7,406,641	7,304,332
Interest credited	336,964	451,031	476,514
Policy acquisition costs and other insurance expenses	1,127,486	1,391,433	1,300,780
Other operating expenses	554,044	538,415	466,717
Interest expense	142,863	96,700	124,307
Collateral finance and securitization expense	22,644	11,441	10,449
Total benefits and expenses	9,673,383	9,895,661	9,683,099
Income before income taxes	744,795	1,008,533	635,254
Provision for income taxes	242,629	324,486	216,417
Net income	$ 502,166	$ 684,047	$ 418,837
Earnings per share
Basic earnings per share (in dollars per share)	$ 7.55	$ 9.88	$ 5.82
Diluted earnings per share (in dollars per share)	7.46	9.78	5.78
Dividends declared per share	$ 1.40	$ 1.26	$ 1.08