PENSION AND OTHER POST-EMPLOYMENT BENEFITS - Target Asset Allocations for Pension and OPEB Portfolio (Details)	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Asset Allocations	100.00%	100.00%
Equities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Asset Allocations	38.00%	38.00%
Fixed income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Asset Allocations	30.00%	30.00%
Hedge funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Asset Allocations	8.00%	8.00%
Real estate
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Asset Allocations	10.00%	10.00%
Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Asset Allocations	8.00%	8.00%
Cash and short-term securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target Asset Allocations	6.00%	6.00%