DERIVATIVES (Details) - USD ($)	Jun. 30, 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	16,000,000	$ 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	$ 15,000,000