EMPLOYEE POST-RETIREMENT BENEFITS - Measured at Fair Value (Details) - CAD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 3,835 | $ 4,576 | |
Percentage of Total Portfolio | 100% | 100% | |
Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 1,998 | $ 1,946 | |
Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 1,205 | 2,065 | |
Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 632 | 565 | $ 417 |
Cash and Cash Equivalents | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 56 | $ 70 | |
Percentage of Total Portfolio | 1% | 2% | |
Cash and Cash Equivalents | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 55 | $ 68 | |
Cash and Cash Equivalents | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 1 | 2 | |
Cash and Cash Equivalents | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Equity Securities, Canadian | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 117 | $ 417 | |
Percentage of Total Portfolio | 3% | 9% | |
Equity Securities, Canadian | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 117 | $ 269 | |
Equity Securities, Canadian | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 148 | |
Equity Securities, Canadian | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Equity Securities, U.S. | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 897 | $ 813 | |
Percentage of Total Portfolio | 24% | 18% | |
Equity Securities, U.S. | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 897 | $ 649 | |
Equity Securities, U.S. | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 164 | |
Equity Securities, U.S. | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Equity Securities, International | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 344 | $ 480 | |
Percentage of Total Portfolio | 9% | 10% | |
Equity Securities, International | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 172 | $ 126 | |
Equity Securities, International | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 172 | 354 | |
Equity Securities, International | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Equity Securities, Global | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 75 | $ 424 | |
Percentage of Total Portfolio | 2% | 9% | |
Equity Securities, Global | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 111 | |
Equity Securities, Global | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 75 | 313 | |
Equity Securities, Global | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Equity Securities, Emerging | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 177 | $ 145 | |
Percentage of Total Portfolio | 5% | 3% | |
Equity Securities, Emerging | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 50 | $ 25 | |
Equity Securities, Emerging | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 127 | 120 | |
Equity Securities, Emerging | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, Canadian Bonds, Federal | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 221 | $ 226 | |
Percentage of Total Portfolio | 6% | 5% | |
Fixed Income Securities, Canadian Bonds, Federal | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Fixed Income Securities, Canadian Bonds, Federal | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 221 | 226 | |
Fixed Income Securities, Canadian Bonds, Federal | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, Canadian Bonds, Provincial | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 249 | $ 331 | |
Percentage of Total Portfolio | 6% | 7% | |
Fixed Income Securities, Canadian Bonds, Provincial | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Fixed Income Securities, Canadian Bonds, Provincial | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 249 | 331 | |
Fixed Income Securities, Canadian Bonds, Provincial | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, Canadian Bonds, Municipal | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 12 | $ 16 | |
Percentage of Total Portfolio | 0% | 0% | |
Fixed Income Securities, Canadian Bonds, Municipal | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Fixed Income Securities, Canadian Bonds, Municipal | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 12 | 16 | |
Fixed Income Securities, Canadian Bonds, Municipal | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, Canadian Bonds, Corporate | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 108 | $ 147 | |
Percentage of Total Portfolio | 3% | 4% | |
Fixed Income Securities, Canadian Bonds, Corporate | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Fixed Income Securities, Canadian Bonds, Corporate | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 108 | 147 | |
Fixed Income Securities, Canadian Bonds, Corporate | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, U.S. Bonds, Federal | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 335 | $ 448 | |
Percentage of Total Portfolio | 9% | 10% | |
Fixed Income Securities, U.S. Bonds, Federal | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 177 | $ 433 | |
Fixed Income Securities, U.S. Bonds, Federal | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 158 | 15 | |
Fixed Income Securities, U.S. Bonds, Federal | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, U.S. Bonds, Municipal | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 1 | $ 1 | |
Percentage of Total Portfolio | 0% | 0% | |
Fixed Income Securities, U.S. Bonds, Municipal | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Fixed Income Securities, U.S. Bonds, Municipal | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 1 | 1 | |
Fixed Income Securities, U.S. Bonds, Municipal | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, U.S. Bonds, Corporate | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 439 | $ 210 | |
Percentage of Total Portfolio | 11% | 5% | |
Fixed Income Securities, U.S. Bonds, Corporate | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 345 | $ 67 | |
Fixed Income Securities, U.S. Bonds, Corporate | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 94 | 143 | |
Fixed Income Securities, U.S. Bonds, Corporate | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, International, Government | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 11 | $ 13 | |
Percentage of Total Portfolio | 0% | 0% | |
Fixed Income Securities, International, Government | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 5 | $ 6 | |
Fixed Income Securities, International, Government | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 6 | 7 | |
Fixed Income Securities, International, Government | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, International, Corporate | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 58 | $ 73 | |
Percentage of Total Portfolio | 1% | 2% | |
Fixed Income Securities, International, Corporate | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Fixed Income Securities, International, Corporate | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 58 | 73 | |
Fixed Income Securities, International, Corporate | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Fixed Income Securities, International, Mortgage-backed | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 37 | $ 47 | |
Percentage of Total Portfolio | 1% | 1% | |
Fixed Income Securities, International, Mortgage-backed | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 36 | $ 42 | |
Fixed Income Securities, International, Mortgage-backed | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 1 | 5 | |
Fixed Income Securities, International, Mortgage-backed | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Net Forward Contract, International | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ (78) | $ 0 | |
Percentage of Total Portfolio | (2.00%) | 0% | |
Net Forward Contract, International | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Net Forward Contract, International | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | (78) | 0 | |
Net Forward Contract, International | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Real estate | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 336 | $ 283 | |
Percentage of Total Portfolio | 9% | 6% | |
Real estate | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Real estate | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Real estate | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 336 | 283 | |
Infrastructure | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 296 | $ 281 | |
Percentage of Total Portfolio | 8% | 6% | |
Infrastructure | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Infrastructure | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Infrastructure | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 296 | 281 | |
Private equity funds | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 1 | |
Percentage of Total Portfolio | 0% | 0% | |
Private equity funds | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |
Private equity funds | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Private equity funds | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 1 | |
Funds held on deposit | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 144 | $ 150 | |
Percentage of Total Portfolio | 4% | 3% | |
Funds held on deposit | Quoted Prices in Active Markets (Level I) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 144 | $ 150 | |
Funds held on deposit | Significant Other Observable Inputs (Level II) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | 0 | 0 | |
Funds held on deposit | Significant Unobservable Inputs (Level III) | | | |
Employee post-retirement benefits | | | |
Fair value of plan assets | $ 0 | $ 0 | |