INVESTMENT OPERATIONS (Details 2) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Investments classified as available-for-sale
Amortized Cost	$ 25,040,468,000	$ 24,162,714,000
Gross Unrealized Gains	1,946,475,000	3,249,825,000
Gross Unrealized Losses	(411,928,000)	(140,780,000)
Fair Value	26,575,015,000	27,271,759,000
Total OTTI Recognized in OCI	2,226,000	(6,134,000)
Fixed maturities
Investments classified as available-for-sale
Amortized Cost	24,531,216,000	23,674,016,000
Gross Unrealized Gains	1,938,007,000	3,237,382,000
Gross Unrealized Losses	(398,790,000)	(130,747,000)
Fair Value	26,070,433,000	26,780,651,000
Total OTTI Recognized in OCI	3,012,000	(6,134,000)
Investments classified as held-to-maturity
Amortized Cost	335,000,000	300,000,000
Gross Unrealized Gains		19,163,000
Gross Unrealized Losses	(1,229,000)
Fair Value	333,771,000	319,163,000
Trading securities	2,900,000,000	3,000,000,000
Amortized Cost
Due in one year or less	543,656,000
Due after one year through five years	4,166,061,000
Due after five years through ten years	6,823,942,000
Due after ten years	12,997,557,000
Total	24,531,216,000
Fair Value
Due in one year or less	550,573,000
Due after one year through five years	4,532,721,000
Due after five years through ten years	7,081,054,000
Due after ten years	13,906,085,000
Total	26,070,433,000
Amortized Cost
Due after ten years	335,000,000
Total	335,000,000	300,000,000
Fair Value
Due after ten years	333,771,000
Fair Value	333,771,000	319,163,000
Residential mortgage-backed securities
Investments classified as available-for-sale
Amortized Cost	1,532,242,000	1,766,440,000
Gross Unrealized Gains	55,117,000	92,265,000
Gross Unrealized Losses	(15,120,000)	(19,375,000)
Fair Value	1,572,239,000	1,839,330,000
Total OTTI Recognized in OCI	3,124,000	(406,000)
Commercial mortgage-backed securities
Investments classified as available-for-sale
Amortized Cost	937,514,000	797,844,000
Gross Unrealized Gains	27,360,000	72,577,000
Gross Unrealized Losses	(22,070,000)	(598,000)
Fair Value	942,804,000	869,823,000
Other asset-backed securities
Investments classified as available-for-sale
Amortized Cost	947,236,000	1,023,649,000
Gross Unrealized Gains	14,798,000	12,788,000
Gross Unrealized Losses	(39,122,000)	(61,424,000)
Fair Value	922,912,000	975,013,000
Total OTTI Recognized in OCI	(112,000)	(241,000)
U.S. government-related securities
Investments classified as available-for-sale
Amortized Cost	1,160,068,000	1,099,001,000
Gross Unrealized Gains	41,132,000	71,537,000
Gross Unrealized Losses	(25,033,000)	(595,000)
Fair Value	1,176,167,000	1,169,943,000
Other government-related securities
Investments classified as available-for-sale
Amortized Cost	62,795,000	93,565,000
Gross Unrealized Gains	2,891,000	7,258,000
Gross Unrealized Losses	(1,000)	(45,000)
Fair Value	65,685,000	100,778,000
States, municipals, and political subdivisions
Investments classified as available-for-sale
Amortized Cost	1,191,794,000	1,188,077,000
Gross Unrealized Gains	149,938,000	255,900,000
Gross Unrealized Losses	(3,987,000)	(264,000)
Fair Value	1,337,745,000	1,443,713,000
Corporate bonds
Investments classified as available-for-sale
Amortized Cost	18,699,567,000	17,705,440,000
Gross Unrealized Gains	1,646,771,000	2,725,057,000
Gross Unrealized Losses	(293,457,000)	(48,446,000)
Fair Value	20,052,881,000	20,382,051,000
Total OTTI Recognized in OCI		(5,487,000)
Other
Investments classified as held-to-maturity
Amortized Cost	335,000,000	300,000,000
Gross Unrealized Gains		19,163,000
Gross Unrealized Losses	(1,229,000)
Fair Value	333,771,000	319,163,000
Amortized Cost
Total	335,000,000	300,000,000
Fair Value
Fair Value	333,771,000	319,163,000
Equity securities
Investments classified as available-for-sale
Amortized Cost	428,805,000	389,821,000
Gross Unrealized Gains	8,468,000	12,443,000
Gross Unrealized Losses	(13,138,000)	(10,033,000)
Fair Value	424,135,000	392,231,000
Total OTTI Recognized in OCI	(786,000)
Investments classified as held-to-maturity
Trading securities	22,400,000	19,600,000
Short-term investments
Investments classified as available-for-sale
Amortized Cost	80,447,000	98,877,000
Fair Value	80,447,000	98,877,000
Investments classified as held-to-maturity
Trading securities	$ 91,600,000	$ 118,900,000