DERIVATIVES (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Aggregate notional amount of interest rate swaps	$ 825,000,000	$ 825,000,000
Face value of medium-term notes	(15,000,000)	$ (7,000,000)
Fair Value Hedging
Derivative [Line Items]
Aggregate notional amount of interest rate swaps	825,000,000
Cash Flow Hedging
Derivative [Line Items]
Aggregate notional amount of interest rate swaps	$ 15,530,000