FAIR VALUE OF FINANCIAL INSTRUMENTS (Details 2) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Determination of fair values
Number of primary sources of information considered for determining fair value	1
Total number of primary sources of information available for determining fair value	3
Minimum percentage of the Company's fixed maturity securities priced by third party pricing services (as a percent)	90.00%
Number of independent non-binding broker quotes obtained per security	1
Percentage of derivatives excluding embedded derivatives that were priced using exchange prices or independent broker quotations (as a percent)	84.70%
Level 2 | Asset-Backed Securities
Determination of fair values
Carrying amount	3,500,000,000
Level 3 | Asset-Backed Securities
Determination of fair values
Carrying amount	678,800,000
Investment grade credit rating (as a percent)	100.00%
Weighted-average yield (as a percent)	0.90%
Par value	683,700,000
Weighted-average stated maturity (in years)	7.5
Other asset-backed securities
Determination of fair values
Percentage of underlying collateral of student-loan backed auction rate securities guaranteed by the Federal Family Education Loan Program ("FFELP"), minimum (as a percent)	97.00%	97.00%
Other asset-backed securities | Level 3 | Trading Securities
Determination of fair values
Carrying amount	41,100,000
Percentage of underlying collateral of student-loan backed auction rate securities guaranteed by the Federal Family Education Loan Program ("FFELP"), minimum (as a percent)	97.00%
Corporate bonds, U.S. Government-related securities, and Other government related securities | Level 2
Determination of fair values
Carrying amount	20,400,000,000
Corporate bonds, U.S. Government-related securities, and Other government related securities | Level 3
Determination of fair values
Carrying amount	178,700,000
Investment grade credit rating (as a percent)	69.60%
Weighted-average yield (as a percent)	4.30%
Weighted-average coupon (as a percent)	4.50%
Par value	194,200,000
Weighted-average stated maturity (in years)	5.7
Equity securities | Level 2 and Level 3
Determination of fair values
Carrying amount	92,200,000
Federal Home Loan Bank Stock	64,600,000
Embedded derivative - GMWB
Annuity account balances
Discount rate curve, base rate	LIBOR
Mortality	65% of 94 GMDB table
Annuity account balances.
Annuity account balances
Discount rate curve, base rate	LIBOR
Asset Earned Rate (as a percent)	5.90%
Admin Expense per Policy	91,000
Partial Withdrawal Rate (for ages less than 70, as a percent)	2.20%
Partial Withdrawal Rate (for ages 70 and greater, as a percent)	2.20%
Mortality	65% of 94 GMDB table
Lapse, low end of the range (as a percent)	2.20%
Lapse, high end of the range(as a percent)	55.00%
Return on Assets, low end of the range (as a percent)	1.50%
Return on Assets, high end of the range (as a percent)	1.85%
Equity indexed annuities, discount rate for one month (as a percent)	0.33%
Equity indexed annuities, discount rate for five years (as a percent)	3.11%
Equity indexed annuities, discount rate for thirty years (as a percent)	5.38%