FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets:
Available-for-sale securities	$ 26,149,476	$ 25,288,601
Trading securities	3,100,000
Total fixed maturity securities	28,832,300	27,957,565	[1]
Equity securities	314,028	292,413	[1]
Other long-term investments	105,674	54,645
Short-term investments	88,348	101,470	[1]
Assets related to separate accounts
Variable annuity	7,949,926	6,741,959	[1]
Variable universal life	530,630	502,617	[1]
Liabilities:
Other liabilities	549,828	455,710
Fixed maturities
Assets:
Available-for-sale securities	25,808,681	24,997,600
Residential mortgage-backed securities
Assets:
Available-for-sale securities	2,127,244	2,337,044
Commercial mortgage-backed securities
Assets:
Available-for-sale securities	745,831	550,527
Other asset-backed securities
Assets:
Available-for-sale securities	921,744	913,029
U.S. government-related securities
Assets:
Available-for-sale securities	1,317,213	1,215,679
States, municipals, and political subdivisions
Assets:
Available-for-sale securities	1,396,086	1,327,713
Other government-related securities
Assets:
Available-for-sale securities	108,176	93,017
Corporate bonds
Assets:
Available-for-sale securities	19,192,387	18,560,591
Measured at fair value on a recurring basis | Level 1
Assets:
Total fixed maturity securities	1,095,016	1,220,311
Equity securities	222,303	211,023
Other long-term investments	23,615	27,757
Short-term investments	88,348	101,470
Total investments	1,429,282	1,560,561
Cash	118,785	169,775
Assets related to separate accounts
Variable annuity	7,949,926	6,741,959
Variable universal life	530,630	502,617
Total assets	10,028,623	8,974,912
Liabilities:
Other liabilities	17,424	2,727
Total liabilities	17,424	2,727
Measured at fair value on a recurring basis | Level 1 | Fixed maturities
Assets:
Available-for-sale securities	784,819	664,710
Trading securities	310,197	555,601
Measured at fair value on a recurring basis | Level 1 | U.S. government-related securities
Assets:
Available-for-sale securities	784,615	664,506
Trading securities	310,197	555,601
Measured at fair value on a recurring basis | Level 1 | Corporate bonds
Assets:
Available-for-sale securities	204	204
Measured at fair value on a recurring basis | Level 2
Assets:
Total fixed maturity securities	26,891,026	25,959,526
Equity securities	21,930	11,310
Other long-term investments	56,744	7,785
Total investments	26,969,700	25,978,621
Assets related to separate accounts
Total assets	26,969,700	25,978,621
Liabilities:
Other liabilities	15,817	15,370
Total liabilities	15,817	15,370
Measured at fair value on a recurring basis | Level 2 | Fixed maturities
Assets:
Available-for-sale securities	24,242,777	23,583,505
Trading securities	2,648,249	2,376,021
Measured at fair value on a recurring basis | Level 2 | Residential mortgage-backed securities
Assets:
Available-for-sale securities	2,127,240	2,337,037
Trading securities	374,068	313,963
Measured at fair value on a recurring basis | Level 2 | Commercial mortgage-backed securities
Assets:
Available-for-sale securities	745,831	550,527
Trading securities	192,125	190,247
Measured at fair value on a recurring basis | Level 2 | Other asset-backed securities
Assets:
Available-for-sale securities	337,103	298,216
Trading securities	69,543	29,585
Measured at fair value on a recurring basis | Level 2 | U.S. government-related securities
Assets:
Available-for-sale securities	532,598	536,173
Trading securities	252	255
Measured at fair value on a recurring basis | Level 2 | States, municipals, and political subdivisions
Assets:
Available-for-sale securities	1,391,811	1,327,713
Trading securities	259,486	229,032
Measured at fair value on a recurring basis | Level 2 | Other government-related securities
Assets:
Available-for-sale securities	88,156	93,017
Trading securities	58,125	44,845
Measured at fair value on a recurring basis | Level 2 | Corporate bonds
Assets:
Available-for-sale securities	19,020,038	18,440,822
Trading securities	1,694,650	1,568,094
Measured at fair value on a recurring basis | Level 3
Assets:
Total fixed maturity securities	846,258	777,728
Equity securities	69,795	70,080
Other long-term investments	25,315	19,103
Total investments	941,368	866,911
Assets related to separate accounts
Total assets	941,368	866,911
Liabilities:
Annuity account balances	134,597	136,462
Other liabilities	516,587	437,613
Total liabilities	651,184	574,075
Measured at fair value on a recurring basis | Level 3 | Fixed maturities
Assets:
Available-for-sale securities	781,085	749,385
Trading securities	65,173	28,343
Measured at fair value on a recurring basis | Level 3 | Residential mortgage-backed securities
Assets:
Available-for-sale securities	4	7
Measured at fair value on a recurring basis | Level 3 | Other asset-backed securities
Assets:
Available-for-sale securities	584,641	614,813
Trading securities	65,059	28,343
Measured at fair value on a recurring basis | Level 3 | U.S. government-related securities
Assets:
Available-for-sale securities		15,000
Measured at fair value on a recurring basis | Level 3 | States, municipals, and political subdivisions
Assets:
Available-for-sale securities	4,275
Measured at fair value on a recurring basis | Level 3 | Other government-related securities
Assets:
Available-for-sale securities	20,020
Measured at fair value on a recurring basis | Level 3 | Corporate bonds
Assets:
Available-for-sale securities	172,145	119,565
Trading securities	114
Measured at fair value on a recurring basis | Total
Assets:
Total fixed maturity securities	28,832,300	27,957,565
Equity securities	314,028	292,413
Other long-term investments	105,674	54,645
Short-term investments	88,348	101,470
Total investments	29,340,350	28,406,093
Cash	118,785	169,775
Assets related to separate accounts
Variable annuity	7,949,926	6,741,959
Variable universal life	530,630	502,617
Total assets	37,939,691	35,820,444
Liabilities:
Annuity account balances	134,597	136,462
Other liabilities	549,828	455,710
Total liabilities	684,425	592,172
Measured at fair value on a recurring basis | Total | Fixed maturities
Assets:
Available-for-sale securities	25,808,681	24,997,600
Trading securities	3,023,619	2,959,965
Measured at fair value on a recurring basis | Total | Residential mortgage-backed securities
Assets:
Available-for-sale securities	2,127,244	2,337,044
Trading securities	374,068	313,963
Measured at fair value on a recurring basis | Total | Commercial mortgage-backed securities
Assets:
Available-for-sale securities	745,831	550,527
Trading securities	192,125	190,247
Measured at fair value on a recurring basis | Total | Other asset-backed securities
Assets:
Available-for-sale securities	921,744	913,029
Trading securities	134,602	57,928
Measured at fair value on a recurring basis | Total | U.S. government-related securities
Assets:
Available-for-sale securities	1,317,213	1,215,679
Trading securities	310,449	555,856
Measured at fair value on a recurring basis | Total | States, municipals, and political subdivisions
Assets:
Available-for-sale securities	1,396,086	1,327,713
Trading securities	259,486	229,032
Measured at fair value on a recurring basis | Total | Other government-related securities
Assets:
Available-for-sale securities	108,176	93,017
Trading securities	58,125	44,845
Measured at fair value on a recurring basis | Total | Corporate bonds
Assets:
Available-for-sale securities	19,192,387	18,560,591
Trading securities	$ 1,694,764	$ 1,568,094

[1] Recast from previously reported information