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 |