MORTGAGE LOANS (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Mortgage loans
Mortgage loan holdings	5,589,795,000
Amount that would become due in remainder of 2015, if loans are called at their next call dates	168,800,000
Amount that would become due in 2016 through 2020, if loans are called at their next call dates	950,400,000
Amount that would become due in 2021 through 2025, if loans are called at their next call dates	381,200,000
Amount that would become due after 2025, if loans are called at their next call dates	119,600,000
Minimum
Mortgage loans
Period for exercise of call options or interest rate reset options	3 years
Maximum
Mortgage loans
Period for exercise of call options or interest rate reset options	10 years