FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Assets:
Available-for-sale securities	$ 33,992,199,000	$ 32,661,058,000
Trading securities	2,900,000,000
Total fixed maturity securities	36,057,560,000	34,797,757,000
Equity securities	672,841,000	602,388,000
Other long-term investments	209,629,000	210,320,000
Short-term investments	193,445,000	133,024,000
Assets related to separate accounts
Variable annuity	12,946,329,000	12,791,438,000
Variable universal life	792,200,000	783,618,000
Liabilities:
Other liabilities	488,174,000	455,161,000
Fixed maturities
Assets:
Available-for-sale securities	33,219,756,000	31,999,267,000
Trading securities	2,800,000,000	2,800,000,000
Residential mortgage-backed securities
Assets:
Available-for-sale securities	1,438,773,000	1,445,068,000
Commercial mortgage-backed securities
Assets:
Available-for-sale securities	1,023,366,000	970,656,000
Other asset-backed securities
Assets:
Available-for-sale securities	860,745,000	871,983,000
U.S. government-related securities
Assets:
Available-for-sale securities	1,511,241,000	1,507,890,000
States, municipalities, and political subdivisions
Assets:
Available-for-sale securities	1,523,940,000	1,410,829,000
Other government-related securities
Assets:
Available-for-sale securities	51,678,000	51,427,000
Corporate bonds
Assets:
Available-for-sale securities	26,810,013,000	25,741,414,000
Measured at fair value on a recurring basis | Level 1
Assets:
Total fixed maturity securities	1,418,039,000	1,402,580,000
Equity securities	509,442,000	483,482,000
Other long-term investments	71,677,000	56,469,000
Short-term investments	181,618,000	131,421,000
Total investments	2,180,776,000	2,073,952,000
Cash	274,514,000	345,579,000
Assets related to separate accounts
Variable annuity	12,946,329,000	12,791,438,000
Variable universal life	792,200,000	783,618,000
Total assets measured at fair value on a recurring basis	16,193,819,000	15,994,587,000
Liabilities:
Other liabilities	24,586,000	30,241,000
Total liabilities measured at fair value on a recurring basis	24,586,000	30,241,000
Measured at fair value on a recurring basis | Level 1 | Fixed maturities
Assets:
Available-for-sale securities	1,214,622,000	1,211,248,000
Trading securities	203,417,000	191,332,000
Measured at fair value on a recurring basis | Level 1 | U.S. government-related securities
Assets:
Available-for-sale securities	1,214,490,000	1,211,141,000
Trading securities	203,417,000	191,332,000
Measured at fair value on a recurring basis | Level 1 | Corporate bonds
Assets:
Available-for-sale securities	132,000	107,000
Measured at fair value on a recurring basis | Level 2
Assets:
Total fixed maturity securities	32,287,704,000	31,071,550,000
Equity securities	85,808,000	50,927,000
Other long-term investments	62,239,000	54,965,000
Short-term investments	11,827,000	1,603,000
Total investments	32,447,578,000	31,179,045,000
Assets related to separate accounts
Total assets measured at fair value on a recurring basis	32,447,578,000	31,179,045,000
Liabilities:
Other liabilities	155,039,000	191,182,000
Total liabilities measured at fair value on a recurring basis	155,039,000	191,182,000
Measured at fair value on a recurring basis | Level 2 | Fixed maturities
Assets:
Available-for-sale securities	29,878,927,000	28,688,568,000
Trading securities	2,408,777,000	2,382,982,000
Measured at fair value on a recurring basis | Level 2 | Residential mortgage-backed securities
Assets:
Available-for-sale securities	1,438,756,000	1,445,040,000
Trading securities	303,729,000	310,877,000
Measured at fair value on a recurring basis | Level 2 | Commercial mortgage-backed securities
Assets:
Available-for-sale securities	1,023,366,000	970,656,000
Trading securities	160,096,000	158,570,000
Measured at fair value on a recurring basis | Level 2 | Other asset-backed securities
Assets:
Available-for-sale securities	311,940,000	326,175,000
Trading securities	90,708,000	93,278,000
Measured at fair value on a recurring basis | Level 2 | U.S. government-related securities
Assets:
Available-for-sale securities	296,751,000	296,749,000
Trading securities	4,973,000	4,906,000
Measured at fair value on a recurring basis | Level 2 | States, municipalities, and political subdivisions
Assets:
Available-for-sale securities	1,520,265,000	1,407,154,000
Trading securities	274,605,000	260,892,000
Measured at fair value on a recurring basis | Level 2 | Other government-related securities
Assets:
Available-for-sale securities	51,678,000	51,427,000
Trading securities	55,044,000	57,097,000
Measured at fair value on a recurring basis | Level 2 | Corporate bonds
Assets:
Available-for-sale securities	25,236,171,000	24,191,367,000
Trading securities	1,519,622,000	1,497,362,000
Measured at fair value on a recurring basis | Level 3
Assets:
Total fixed maturity securities	2,351,817,000	2,323,627,000
Equity securities	77,591,000	67,979,000
Other long-term investments	75,713,000	98,886,000
Total investments	2,505,121,000	2,490,492,000
Assets related to separate accounts
Total assets measured at fair value on a recurring basis	2,505,121,000	2,490,492,000
Liabilities:
Annuity account balances	105,593,000	107,000,000
Other liabilities	308,549,000	233,738,000
Total liabilities measured at fair value on a recurring basis	414,142,000	340,738,000
Measured at fair value on a recurring basis | Level 3 | Fixed maturities
Assets:
Available-for-sale securities	2,126,207,000	2,099,451,000
Trading securities	225,610,000	224,176,000
Measured at fair value on a recurring basis | Level 3 | Residential mortgage-backed securities
Assets:
Available-for-sale securities	17,000	28,000
Measured at fair value on a recurring basis | Level 3 | Other asset-backed securities
Assets:
Available-for-sale securities	548,805,000	545,808,000
Trading securities	194,664,000	194,977,000
Measured at fair value on a recurring basis | Level 3 | States, municipalities, and political subdivisions
Assets:
Available-for-sale securities	3,675,000	3,675,000
Measured at fair value on a recurring basis | Level 3 | Corporate bonds
Assets:
Available-for-sale securities	1,573,710,000	1,549,940,000
Trading securities	30,946,000	29,199,000
Measured at fair value on a recurring basis | Total
Assets:
Total fixed maturity securities	36,057,560,000	34,797,757,000
Equity securities	672,841,000	602,388,000
Other long-term investments	209,629,000	210,320,000
Short-term investments	193,445,000	133,024,000
Total investments	37,133,475,000	35,743,489,000
Cash	274,514,000	345,579,000
Assets related to separate accounts
Variable annuity	12,946,329,000	12,791,438,000
Variable universal life	792,200,000	783,618,000
Total assets measured at fair value on a recurring basis	51,146,518,000	49,664,124,000
Liabilities:
Annuity account balances	105,593,000	107,000,000
Other liabilities	488,174,000	455,161,000
Total liabilities measured at fair value on a recurring basis	593,767,000	562,161,000
Measured at fair value on a recurring basis | Total | Fixed maturities
Assets:
Available-for-sale securities	33,219,756,000	31,999,267,000
Trading securities	2,837,804,000	2,798,490,000
Measured at fair value on a recurring basis | Total | Residential mortgage-backed securities
Assets:
Available-for-sale securities	1,438,773,000	1,445,068,000
Trading securities	303,729,000	310,877,000
Measured at fair value on a recurring basis | Total | Commercial mortgage-backed securities
Assets:
Available-for-sale securities	1,023,366,000	970,656,000
Trading securities	160,096,000	158,570,000
Measured at fair value on a recurring basis | Total | Other asset-backed securities
Assets:
Available-for-sale securities	860,745,000	871,983,000
Trading securities	285,372,000	288,255,000
Measured at fair value on a recurring basis | Total | U.S. government-related securities
Assets:
Available-for-sale securities	1,511,241,000	1,507,890,000
Trading securities	208,390,000	196,238,000
Measured at fair value on a recurring basis | Total | States, municipalities, and political subdivisions
Assets:
Available-for-sale securities	1,523,940,000	1,410,829,000
Trading securities	274,605,000	260,892,000
Measured at fair value on a recurring basis | Total | Other government-related securities
Assets:
Available-for-sale securities	51,678,000	51,427,000
Trading securities	55,044,000	57,097,000
Measured at fair value on a recurring basis | Total | Corporate bonds
Assets:
Available-for-sale securities	26,810,013,000	25,741,414,000
Trading securities	$ 1,550,568,000	$ 1,526,561,000