INVESTMENT OPERATIONS (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011		Dec. 31, 2010
Fair Value
Less Than 12 Months	$ 1,574,080,000	$ 2,828,967,000
12 Months or More	793,440,000	1,260,898,000
Total	2,367,520,000	4,089,865,000
Unrealized Loss
Less Than 12 Months	(68,035,000)	(192,058,000)
12 Months or More	(72,622,000)	(255,294,000)
Total	(140,657,000)	(447,352,000)
Available-for-sale securities, fair value	27,214,682,000	25,288,601,000
Available-for-sale securities, amortized cost	24,104,126,000	23,451,332,000
Non-income producing investments	12,200,000
Policy loans	865,391,000	879,819,000	[1]
Interest rate on collateral loans on life insurance policies (as a percent)	13.64%
Securities Lending
Other-than-temporary impairment recognized on certain collateral assets	1,300,000
Balance of collateral assets	3,700,000
Minimum
Unrealized Loss
Interest rate on standard policy loans (as a percent)	3.00%
Maximum
Unrealized Loss
Interest rate on standard policy loans (as a percent)	8.00%
Below investment grade
Unrealized Loss
Available-for-sale securities, fair value	1,700,000,000
Available-for-sale securities, amortized cost	1,700,000,000
Securities in trading portfolio	367,100,000
Securities not publicly traded	415,100,000
Fixed maturities
Unrealized Loss
Available-for-sale securities, fair value	26,762,670,000	24,997,600,000
Available-for-sale securities, amortized cost	23,654,002,000	23,149,166,000
Securities in trading portfolio	3,000,000,000	3,000,000,000
Change in unrealized gains (losses), net of income tax	819,152,000	761,738,000		696,942,000
Residential mortgage-backed securities
Fair Value
Less Than 12 Months	100,412,000	276,216,000
12 Months or More	166,000,000	524,251,000
Total	266,412,000	800,467,000
Unrealized Loss
Less Than 12 Months	(9,578,000)	(15,308,000)
12 Months or More	(9,769,000)	(70,394,000)
Total	(19,347,000)	(85,702,000)
Available-for-sale securities, fair value	1,839,330,000	2,337,044,000
Available-for-sale securities, amortized cost	1,766,260,000	2,340,172,000
Commercial mortgage-backed securities
Fair Value
Less Than 12 Months	50,506,000	78,893,000
Total	50,506,000	78,893,000
Unrealized Loss
Less Than 12 Months	(598,000)	(4,229,000)
Total	(598,000)	(4,229,000)
Available-for-sale securities, fair value	869,823,000	550,527,000
Available-for-sale securities, amortized cost	797,844,000	530,283,000
Other asset-backed securities
Fair Value
Less Than 12 Months	479,223,000	531,653,000
12 Months or More	242,558,000	190,639,000
Total	721,781,000	722,292,000
Unrealized Loss
Less Than 12 Months	(28,179,000)	(32,074,000)
12 Months or More	(33,245,000)	(58,824,000)
Total	(61,424,000)	(90,898,000)
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	975,013,000	913,029,000
Available-for-sale securities, amortized cost	1,023,649,000	997,398,000
U.S. government-related securities
Fair Value
Less Than 12 Months	106,806,000	21,311,000
Total	106,806,000	21,311,000
Unrealized Loss
Less Than 12 Months	(591,000)	(58,000)
Total	(591,000)	(58,000)
Available-for-sale securities, fair value	1,168,446,000	1,215,679,000
Available-for-sale securities, amortized cost	1,097,501,000	1,150,525,000
Other government-related securities
Fair Value
Less Than 12 Months	14,955,000
Total	14,955,000
Unrealized Loss
Less Than 12 Months	(45,000)
Total	(45,000)
Available-for-sale securities, fair value	100,778,000	93,017,000
Available-for-sale securities, amortized cost	93,565,000	88,058,000
States, municipals, and political subdivisions
Fair Value
Less Than 12 Months	11,526,000
Total	11,526,000
Unrealized Loss
Less Than 12 Months	(264,000)
Total	(264,000)
Available-for-sale securities, fair value	1,443,653,000	1,327,713,000
Available-for-sale securities, amortized cost	1,188,019,000	1,154,307,000
Corporate bonds
Fair Value
Less Than 12 Months	775,593,000	1,870,256,000
12 Months or More	363,128,000	523,913,000
Total	1,138,721,000	2,394,169,000
Unrealized Loss
Less Than 12 Months	(23,630,000)	(131,953,000)
12 Months or More	(24,765,000)	(117,917,000)
Total	(48,395,000)	(249,870,000)
Available-for-sale securities, fair value	20,365,627,000	18,560,591,000
Available-for-sale securities, amortized cost	17,687,164,000	16,888,423,000
Equity securities
Fair Value
Less Than 12 Months	35,059,000	50,638,000
12 Months or More	21,754,000	22,095,000
Total	56,813,000	72,733,000
Unrealized Loss
Less Than 12 Months	(5,150,000)	(8,436,000)
12 Months or More	(4,843,000)	(8,159,000)
Total	(9,993,000)	(16,595,000)
Available-for-sale securities, fair value	354,160,000	275,372,000
Available-for-sale securities, amortized cost	352,272,000	286,537,000
Securities in trading portfolio	19,600,000	17,000,000
Change in unrealized gains (losses), net of income tax	$ 8,484,000	$ (13,292,000)		$ 9,701,000

[1] Recast from previously reported information