INVESTMENT OPERATIONS (Details 2) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
INVESTMENT OPERATIONS
Amortized Cost	$ 23,752,892,000	$ 23,451,332,000
Gross Unrealized Gains	2,682,022,000	2,284,621,000
Gross Unrealized Losses	(285,438,000)	(447,352,000)
Fair Value	26,149,476,000	25,288,601,000
Total OTTI Recognized in OCI	(44,113,000)	(52,498,000)
Amortized Cost
Due in one year or less	469,467,000
Due after one year through five years	4,754,021,000
Due after five years through ten years	5,726,983,000
Due after ten years	12,456,146,000
Total	23,406,617,000
Fair Value
Due in one year or less	474,255,000
Due after one year through five years	5,072,983,000
Due after five years through ten years	6,250,795,000
Due after ten years	14,010,648,000
Total	25,808,681,000
Fixed maturities:
INVESTMENT OPERATIONS
Amortized Cost	23,406,617,000	23,149,166,000
Gross Unrealized Gains	2,674,853,000	2,279,191,000
Gross Unrealized Losses	(272,789,000)	(430,757,000)
Fair Value	25,808,681,000	24,997,600,000
Total OTTI Recognized in OCI	(44,113,000)	(52,424,000)
Trading securities	3,000,000,000	3,000,000,000
Residential mortgage-backed securities
INVESTMENT OPERATIONS
Amortized Cost	2,089,252,000	2,340,172,000
Gross Unrealized Gains	94,902,000	82,574,000
Gross Unrealized Losses	(56,910,000)	(85,702,000)
Fair Value	2,127,244,000	2,337,044,000
Total OTTI Recognized in OCI	(30,802,000)	(47,652,000)
Commercial mortgage-backed securities
INVESTMENT OPERATIONS
Amortized Cost	710,465,000	530,283,000
Gross Unrealized Gains	36,681,000	24,473,000
Gross Unrealized Losses	(1,315,000)	(4,229,000)
Fair Value	745,831,000	550,527,000
Other asset-backed securities
INVESTMENT OPERATIONS
Amortized Cost	1,008,490,000	997,398,000
Gross Unrealized Gains	6,817,000	6,529,000
Gross Unrealized Losses	(93,563,000)	(90,898,000)
Fair Value	921,744,000	913,029,000
Total OTTI Recognized in OCI	(8,307,000)	(6,559,000)
U.S. government-related securities
INVESTMENT OPERATIONS
Amortized Cost	1,239,475,000	1,150,525,000
Gross Unrealized Gains	77,738,000	65,212,000
Gross Unrealized Losses		(58,000)
Fair Value	1,317,213,000	1,215,679,000
Other government-related securities
INVESTMENT OPERATIONS
Amortized Cost	101,521,000	88,058,000
Gross Unrealized Gains	6,792,000	4,959,000
Gross Unrealized Losses	(137,000)
Fair Value	108,176,000	93,017,000
States, municipals, and political subdivisions
INVESTMENT OPERATIONS
Amortized Cost	1,158,642,000	1,154,307,000
Gross Unrealized Gains	237,453,000	173,406,000
Gross Unrealized Losses	(9,000)
Fair Value	1,396,086,000	1,327,713,000
Corporate bonds
INVESTMENT OPERATIONS
Amortized Cost	17,098,772,000	16,888,423,000
Gross Unrealized Gains	2,214,470,000	1,922,038,000
Gross Unrealized Losses	(120,855,000)	(249,870,000)
Fair Value	19,192,387,000	18,560,591,000
Total OTTI Recognized in OCI	(5,004,000)	1,787,000
Equity securities
INVESTMENT OPERATIONS
Amortized Cost	301,329,000	286,537,000
Gross Unrealized Gains	7,169,000	5,430,000
Gross Unrealized Losses	(12,649,000)	(16,595,000)
Fair Value	295,849,000	275,372,000
Total OTTI Recognized in OCI		(74,000)
Trading securities	18,200,000	17,000,000
Short-term investments
INVESTMENT OPERATIONS
Amortized Cost	44,946,000	15,629,000
Fair Value	44,946,000	15,629,000
Trading securities	$ 43,400,000	$ 85,800,000