PENSION AND OTHER POST-EMPLOYMENT BENEFIT PLANS - Net Pension Plan Assets, by Fair Value Hierarchy (Details) - Pension - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Cash and short-term investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	$ 73	$ 412
Cash and short-term investments | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	5	5
Public equity investments | Qualified and Registered Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	18	0
Fixed Income Investments, Corporate | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	874	1,380
Fixed Income Investments, Government | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	316	721
Fixed Income Investments, Repurchase Agreements | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	(12)	(43)
Hedge funds and related investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	16	10
Private equity and related investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	34	104
Derivative instruments, net | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	5
Pension trust investments measured at fair value | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	1,319	2,589
Public equity investments | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	3	6
Canadian nonregistered plan assets measured at fair value | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	8	11
Pension plans defined benefit excluding hedge fund and private equity investments and accrued liabilities
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	1,327	2,600
Fair Value, Inputs, Level 1 | Cash and short-term investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	73	412
Fair Value, Inputs, Level 1 | Cash and short-term investments | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	5	5
Fair Value, Inputs, Level 1 | Public equity investments | Qualified and Registered Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	18	0
Fair Value, Inputs, Level 1 | Fixed Income Investments, Corporate | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 1 | Fixed Income Investments, Government | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 1 | Fixed Income Investments, Repurchase Agreements | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 1 | Hedge funds and related investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 1 | Private equity and related investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 1 | Derivative instruments, net | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 1 | Pension trust investments measured at fair value | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	91	412
Fair Value, Inputs, Level 1 | Public equity investments | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	3	6
Fair Value, Inputs, Level 1 | Canadian nonregistered plan assets measured at fair value | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	8	11
Fair Value, Inputs, Level 2 | Cash and short-term investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 2 | Cash and short-term investments | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 2 | Public equity investments | Qualified and Registered Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 2 | Fixed Income Investments, Corporate | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	874	1,380
Fair Value, Inputs, Level 2 | Fixed Income Investments, Government | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	316	721
Fair Value, Inputs, Level 2 | Fixed Income Investments, Repurchase Agreements | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	(12)	(43)
Fair Value, Inputs, Level 2 | Hedge funds and related investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 2 | Private equity and related investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 2 | Derivative instruments, net | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	5
Fair Value, Inputs, Level 2 | Pension trust investments measured at fair value | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	1,178	2,063
Fair Value, Inputs, Level 2 | Public equity investments | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 2 | Canadian nonregistered plan assets measured at fair value | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 3 | Cash and short-term investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 3 | Cash and short-term investments | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 3 | Public equity investments | Qualified and Registered Plans
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 3 | Fixed Income Investments, Corporate | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 3 | Fixed Income Investments, Government | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 3 | Fixed Income Investments, Repurchase Agreements | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 3 | Hedge funds and related investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	16	10
Fair Value, Inputs, Level 3 | Private equity and related investments | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	34	104
Fair Value, Inputs, Level 3 | Derivative instruments, net | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 3 | Pension trust investments measured at fair value | Qualified and Registered Plans | U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	50	114
Fair Value, Inputs, Level 3 | Public equity investments | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	0	0
Fair Value, Inputs, Level 3 | Canadian nonregistered plan assets measured at fair value | Non Registered Plans | Canada
Defined Benefit Plan Disclosure [Line Items]
Fair value of net plan assets	$ 0	$ 0