RISK MANAGEMENT AND FINANCIAL INSTRUMENTS - MARKET RISK (Details)	Dec. 31, 2019
Maximum
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
Policy limit increase (percent)	30.00%
Interest Rate Swaption
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
Average swap rate (as a percent)	2.90%
Interest rate contracts - long-term borrowings
RISK MANAGEMENT AND FINANCIAL INSTRUMENTS
Average swap rate (as a percent)	3.00%