INVESTMENTS - SUMMARY OF INVESTMENTS BY CONTRACTUAL MATURITY (DETAILS) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Amortized Cost
Due in one year or less	$ 118.8
Due after one year through five years	1,719.2
Due after five years through ten years	3,042.5
Due after ten years	9,506.8
Subtotal	14,387.3
Structured securities	4,078.3
Total fixed maturities, available for sale	18,465.6	21,860.6
Estimated Fair Value
Due in one year or less	120.9
Due after one year through five years	1,889.3
Due after five years through ten years	3,307.6
Due after ten years	10,506.5
Subtotal	15,824.3
Structured securities	4,319.5
Total fixed maturities, available for sale	$ 20,143.8	$ 23,178.3