INVESTMENT OPERATIONS (Details 4) (USD $)	9 Months Ended			3 Months Ended		9 Months Ended							9 Months Ended	12 Months Ended									3 Months Ended		9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Below investment grade	Sep. 30, 2012 Fixed maturities	Sep. 30, 2011 Fixed maturities	Sep. 30, 2012 Fixed maturities	Sep. 30, 2011 Fixed maturities	Dec. 31, 2011 Fixed maturities	Sep. 30, 2012 Residential mortgage-backed securities	Dec. 31, 2011 Residential mortgage-backed securities	Sep. 30, 2012 Commercial mortgage-backed securities	Dec. 31, 2011 Commercial mortgage-backed securities	Sep. 30, 2012 Other asset-backed securities	Dec. 31, 2011 Other asset-backed securities	Sep. 30, 2012 U.S. government-related securities	Dec. 31, 2011 U.S. government-related securities	Sep. 30, 2012 Other government-related securities	Dec. 31, 2011 Other government-related securities	Sep. 30, 2012 States, municipals, and political subdivisions	Dec. 31, 2011 States, municipals, and political subdivisions	Sep. 30, 2012 Corporate bonds	Dec. 31, 2011 Corporate bonds	Sep. 30, 2012 Equity securities	Sep. 30, 2011 Equity securities	Sep. 30, 2012 Equity securities	Sep. 30, 2011 Equity securities	Dec. 31, 2011 Equity securities
Fair Value
Less Than 12 Months	$ 1,277,095,000	$ 2,828,967,000							$ 65,010,000	$ 276,216,000	$ 18,629,000	$ 78,893,000	$ 511,822,000	$ 531,653,000	$ 51,377,000	$ 21,311,000	$ 34,994,000		$ 10,302,000		$ 569,790,000	$ 1,870,256,000	$ 15,171,000		$ 15,171,000		$ 50,638,000
12 Months or More	987,960,000	1,260,898,000							229,183,000	524,251,000			202,059,000	190,639,000							535,333,000	523,913,000	21,385,000		21,385,000		22,095,000
Total	2,265,055,000	4,089,865,000							294,193,000	800,467,000	18,629,000	78,893,000	713,881,000	722,292,000	51,377,000	21,311,000	34,994,000		10,302,000		1,105,123,000	2,394,169,000	36,556,000		36,556,000		72,733,000
Unrealized Loss
Less Than 12 Months	(71,233,000)	(192,058,000)							(5,709,000)	(15,308,000)	(332,000)	(4,229,000)	(36,646,000)	(32,074,000)	(173,000)	(58,000)	(19,000)		(215,000)		(23,199,000)	(131,953,000)	(4,940,000)		(4,940,000)		(8,436,000)
12 Months or More	(101,963,000)	(255,294,000)							(18,287,000)	(70,394,000)			(38,301,000)	(58,824,000)							(40,113,000)	(117,917,000)	(5,262,000)		(5,262,000)		(8,159,000)
Total	(173,196,000)	(447,352,000)							(23,996,000)	(85,702,000)	(332,000)	(4,229,000)	(74,947,000)	(90,898,000)	(173,000)	(58,000)	(19,000)		(215,000)		(63,312,000)	(249,870,000)	(10,202,000)		(10,202,000)		(16,595,000)
Percentage of underlying collateral including student-loan backed auction rate securities guaranteed by the Federal Family Education Loan Program ("FFELP"), minimum													97.00%	97.00%
Available-for-sale securities, fair value	26,863,312,000	25,288,601,000	1,700,000,000	26,492,248,000		26,492,248,000		24,997,600,000	2,007,017,000	2,337,044,000	838,657,000	550,527,000	936,063,000	913,029,000	1,349,193,000	1,215,679,000	101,116,000	93,017,000	1,420,997,000	1,327,713,000	19,839,205,000	18,560,591,000	316,931,000		316,931,000		275,372,000
Available-for-sale securities, amortized cost	23,787,928,000	23,451,332,000	1,700,000,000	23,418,354,000		23,418,354,000		23,149,166,000	1,927,396,000	2,340,172,000	772,697,000	530,283,000	999,155,000	997,398,000	1,270,838,000	1,150,525,000	93,490,000	88,058,000	1,168,483,000	1,154,307,000	17,186,295,000	16,888,423,000	315,441,000		315,441,000		286,537,000
Securities in trading portfolio			379,900,000	3,100,000,000		3,100,000,000		3,000,000,000															19,300,000		19,300,000		17,000,000
Securities not publicly traded			455,800,000
Initial collateral as a percentage of market value of securities loaned	102.00%
Other-than-temporary impairment recognized on certain collateral assets	1,300,000
Change in unrealized gains (losses), net of income tax				$ 436,690,000	$ 477,641,000	$ 796,549,000	$ 675,040,000																$ 4,531,000	$ (8,380,000)	$ 8,226,000	$ (12,173,000)