EMPLOYEE BENEFITS - Summary of Plan Assets (Details) - Postretirement Benefits - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan assets	$ 173	$ 162	$ 207
Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan assets	163	153
Funds – municipal/provincial bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan assets	$ 0	8
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	Fair Value, Inputs, Level 1 [Member]
Funds – corporate bonds fund
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan assets	$ 10	3
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	Fair Value, Inputs, Level 1 [Member]
Corporate bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan assets	$ 56	57
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	Fair Value, Inputs, Level 2 [Member]
Government/municipal bonds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan assets	$ 9	12
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	Fair Value, Inputs, Level 2 [Member]
Equity funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan assets	$ 88	73
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	Fair Value, Inputs, Level 2 [Member]
Trust Assets and Liabilities, Net
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan assets	$ 10	$ 9