XML 224 R194.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Segments Disclosures - Reported Segment Earnings (Loss) and Segment Assets (Details) - CAD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Disclosure of operating segments [line items] |  |  |
Revenue | $ 2,845 | $ 3,355 | $ 2,976
Fuel and purchased power | 939 | 1,060 | 1,263
Carbon compliance | 112 | 112 | 78
Gross margin | 1,794 | 2,183 | 1,635
OM&A | 655 |  | 521
Taxes, other than income taxes | 36 | 29 | 33
Net other operating loss (income) | (59) | (47) | (58)
Equity income | 5 | 4 | 9
Finance lease income | 14 | 12 | 19
Depreciation and amortization (Note 19, 20, 21 and 27) | (531) | (621) | (599)
Asset impairment charges | (46) | 48 | (9)
Interest income | 30 | 59 | 24
Interest expense | 324 | 281 | 286
Foreign exchange gain (loss) | 5 | (7) | 4
Gain on sale of assets and other | 4 | 4 | 52
Earnings before income taxes | 319 | 880 | 353
Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 2,845 | 3,355 | 2,976
Fuel and purchased power | 939 | 1,060 | 1,263
OM&A | 655 | 539 | 521
Net other operating loss (income) | (59) | (47) | (58)
Operating segments |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 2,875 | 3,326 | 3,495
Fuel and purchased power | 934 | 1,056 | 1,259
Carbon compliance | 112 | 112 | 78
Gross margin | 1,829 | 2,158 | 2,158
OM&A | 590 |  | 521
Taxes, other than income taxes | 36 | 30 | 35
Net other operating loss (income) | (50) | (46) | (54)
Adjusted EBITDA | 1,253 | 1,632 | 1,656
Operating segments | Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 2,866 | 3,376 | 2,990
Fuel and purchased power | 939 | 1,060 | 1,263
OM&A | 659 | 542 | 523
Net other operating loss (income) | (59) | (47) | (61)
Operating segments | Unrealized mark-to-market (gain) loss |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 3 | (37) | 378
Operating segments | Realized gain (loss) on closed exchange positions |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (6) | (81) | 43
Operating segments | Decrease in finance lease receivable |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 21 | 55 | 46
Operating segments | Finance lease income |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 14 | 12 | 19
Operating segments | Revenues from Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (1) |  |
Operating segments | Brazeau penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (20) |  | 20
OM&A | (31) |  | (2)
Operating segments | Unrealized foreign exchange gain on commodity |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (2) | 1 | (1)
Operating segments | Fuel and purchased power related to Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | (1) |  |
Operating segments | Australian interest income |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | (4) | (4) | (4)
Operating segments | ERP integration costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | (14) |  |
Operating segments | Acquisition-related transaction and restructuring costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | (24) |  |
Operating segments | Sundance A decommissioning cost reimbursement |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) | 9 |  |
Operating segments | Insurance recovery |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  | 1 |
Operating segments | Royalty onerous contract and contract termination penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  |  | 7
Material reconciling items |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (9) | 50 | (505)
Fuel and purchased power | 5 | 4 | 4
Carbon compliance | 0 | 0 | 0
Gross margin | (14) | 46 | (509)
OM&A | 69 |  | 2
Taxes, other than income taxes | 0 | 0 | 0
Net other operating loss (income) | (9) | (1) | (7)
Material reconciling items | Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 |
Fuel and purchased power | 0 | 0 | 0
OM&A | 0 | 0 | 0
Net other operating loss (income) | 0 | 0 | 0
Material reconciling items | Unrealized mark-to-market (gain) loss |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (3) | 37 | (378)
Material reconciling items | Realized gain (loss) on closed exchange positions |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 6 | 81 | (43)
Material reconciling items | Decrease in finance lease receivable |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (21) | (55) | (46)
Material reconciling items | Finance lease income |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (14) | (12) | (19)
Material reconciling items | Revenues from Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 1 |  |
Material reconciling items | Brazeau penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 20 |  | (20)
OM&A | 31 |  | 2
Material reconciling items | Unrealized foreign exchange gain on commodity |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 2 | (1) | 1
Material reconciling items | Fuel and purchased power related to Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 1 |  |
Material reconciling items | Australian interest income |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 4 | 4 | 4
Material reconciling items | ERP integration costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 14 |  |
Material reconciling items | Acquisition-related transaction and restructuring costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 24 |  |
Material reconciling items | Sundance A decommissioning cost reimbursement |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) | (9) |  |
Material reconciling items | Insurance recovery |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  | (1) |
Material reconciling items | Royalty onerous contract and contract termination penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  |  | (7)
Material reconciling items | Equity- accounted investments |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (21) | (21) | (14)
Fuel and purchased power | 0 | 0 | 0
Carbon compliance | 0 | 0 | 0
Gross margin | (21) | (21) | (14)
OM&A | (4) |  | (2)
Taxes, other than income taxes | 0 | (1) | (2)
Net other operating loss (income) | 0 | 0 | 3
Material reconciling items | Equity- accounted investments | Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (21) | (21) | (14)
Fuel and purchased power | 0 | 0 | 0
OM&A | (4) | (3) | (2)
Net other operating loss (income) | 0 |  | 3
Material reconciling items | Equity- accounted investments | Unrealized mark-to-market (gain) loss |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Material reconciling items | Equity- accounted investments | Realized gain (loss) on closed exchange positions |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Material reconciling items | Equity- accounted investments | Decrease in finance lease receivable |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Material reconciling items | Equity- accounted investments | Finance lease income |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Material reconciling items | Equity- accounted investments | Revenues from Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  |
Material reconciling items | Equity- accounted investments | Brazeau penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  | 0
OM&A | 0 |  | 0
Material reconciling items | Equity- accounted investments | Unrealized foreign exchange gain on commodity |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Material reconciling items | Equity- accounted investments | Fuel and purchased power related to Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 |  |
Material reconciling items | Equity- accounted investments | Australian interest income |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 | 0 | 0
Material reconciling items | Equity- accounted investments | ERP integration costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Material reconciling items | Equity- accounted investments | Acquisition-related transaction and restructuring costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A |  |  |
Material reconciling items | Equity- accounted investments | Sundance A decommissioning cost reimbursement |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) | 0 |  |
Material reconciling items | Equity- accounted investments | Insurance recovery |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  | 0 |
Material reconciling items | Equity- accounted investments | Royalty onerous contract and contract termination penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  |  | 0
Hydro | Operating segments |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 390 | 529 | 627
Fuel and purchased power | 16 | 19 | 22
Carbon compliance | 0 | 0 | 0
Gross margin | 374 | 510 | 605
OM&A | 55 |  | 53
Taxes, other than income taxes | 3 | 3 | 3
Net other operating loss (income) | 0 | 0 | 0
Adjusted EBITDA | 316 | 459 | 549
Hydro | Operating segments | Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 409 | 533 | 606
Fuel and purchased power | 16 | 19 | 22
OM&A | 86 | 48 | 55
Net other operating loss (income) | 0 | 0 | 0
Hydro | Operating segments | Unrealized mark-to-market (gain) loss |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 1 | (4) | 1
Hydro | Operating segments | Realized gain (loss) on closed exchange positions |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Hydro | Operating segments | Decrease in finance lease receivable |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Hydro | Operating segments | Finance lease income |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Hydro | Operating segments | Revenues from Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  |
Hydro | Operating segments | Brazeau penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (20) |  | 20
OM&A | (31) |  | (2)
Hydro | Operating segments | Unrealized foreign exchange gain on commodity |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Hydro | Operating segments | Fuel and purchased power related to Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 |  |
Hydro | Operating segments | Australian interest income |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 | 0 | 0
Hydro | Operating segments | ERP integration costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Hydro | Operating segments | Acquisition-related transaction and restructuring costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Hydro | Operating segments | Sundance A decommissioning cost reimbursement |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) | 0 |  |
Hydro | Operating segments | Insurance recovery |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  | 0 |
Hydro | Operating segments | Royalty onerous contract and contract termination penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  |  | 0
Wind and Solar | Operating segments |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 449 | 373 | 407
Fuel and purchased power | 30 | 30 | 31
Carbon compliance | 0 | 0 | 1
Gross margin | 419 | 343 | 375
OM&A | 97 |  | 68
Taxes, other than income taxes | 16 | 12 | 12
Net other operating loss (income) | (10) | (6) | (16)
Adjusted EBITDA | 316 | 257 | 311
Wind and Solar | Operating segments | Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 357 | 357 | 303
Fuel and purchased power | 30 | 30 | 31
OM&A | 97 | 80 | 68
Net other operating loss (income) | (10) | (7) | (23)
Wind and Solar | Operating segments | Unrealized mark-to-market (gain) loss |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 84 | 16 | 104
Wind and Solar | Operating segments | Realized gain (loss) on closed exchange positions |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Wind and Solar | Operating segments | Decrease in finance lease receivable |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 2 | 0 | 0
Wind and Solar | Operating segments | Finance lease income |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 6 | 0 | 0
Wind and Solar | Operating segments | Revenues from Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  |
Wind and Solar | Operating segments | Brazeau penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  | 0
OM&A | 0 |  | 0
Wind and Solar | Operating segments | Unrealized foreign exchange gain on commodity |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Wind and Solar | Operating segments | Fuel and purchased power related to Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 |  |
Wind and Solar | Operating segments | Australian interest income |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 | 0 | 0
Wind and Solar | Operating segments | ERP integration costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Wind and Solar | Operating segments | Acquisition-related transaction and restructuring costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Wind and Solar | Operating segments | Sundance A decommissioning cost reimbursement |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) | 0 |  |
Wind and Solar | Operating segments | Insurance recovery |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  | 1 |
Wind and Solar | Operating segments | Royalty onerous contract and contract termination penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  |  | 7
Gas | Operating segments |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 1,321 | 1,525 | 1,521
Fuel and purchased power | 470 | 449 | 637
Carbon compliance | 145 | 112 | 83
Gross margin | 706 | 964 | 801
OM&A | 198 |  | 195
Taxes, other than income taxes | 13 | 11 | 15
Net other operating loss (income) | (40) | (40) | (38)
Adjusted EBITDA | 535 | 801 | 629
Gas | Operating segments | Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 1,350 | 1,514 | 1,209
Fuel and purchased power | 475 | 453 | 641
OM&A | 198 | 192 | 195
Net other operating loss (income) | (40) | (40) | (38)
Gas | Operating segments | Unrealized mark-to-market (gain) loss |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (60) | (67) | 251
Gas | Operating segments | Realized gain (loss) on closed exchange positions |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 7 | 10 | (4)
Gas | Operating segments | Decrease in finance lease receivable |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 19 | 55 | 46
Gas | Operating segments | Finance lease income |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 8 | 12 | 19
Gas | Operating segments | Revenues from Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (1) |  |
Gas | Operating segments | Brazeau penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  | 0
OM&A | 0 |  | 0
Gas | Operating segments | Unrealized foreign exchange gain on commodity |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (2) | 1 | 0
Gas | Operating segments | Fuel and purchased power related to Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | (1) |  |
Gas | Operating segments | Australian interest income |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | (4) | (4) | (4)
Gas | Operating segments | ERP integration costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Gas | Operating segments | Acquisition-related transaction and restructuring costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Gas | Operating segments | Sundance A decommissioning cost reimbursement |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) | 0 |  |
Gas | Operating segments | Insurance recovery |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  | 0 |
Gas | Operating segments | Royalty onerous contract and contract termination penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  |  | 0
Energy Transition | Operating segments |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 582 | 746 | 724
Fuel and purchased power | 418 | 557 | 566
Carbon compliance | 1 | 0 | (1)
Gross margin | 163 | 189 | 159
OM&A | 69 |  | 69
Taxes, other than income taxes | 3 | 3 | 4
Net other operating loss (income) | 0 | 0 | 0
Adjusted EBITDA | 91 | 122 | 86
Energy Transition | Operating segments | Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 616 | 751 | 714
Fuel and purchased power | 418 | 557 | 566
OM&A | 69 | 64 | 69
Net other operating loss (income) | (9) | 0 | 0
Energy Transition | Operating segments | Unrealized mark-to-market (gain) loss |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (36) | (5) | 10
Energy Transition | Operating segments | Realized gain (loss) on closed exchange positions |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 2 | 0 | 0
Energy Transition | Operating segments | Decrease in finance lease receivable |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Energy Transition | Operating segments | Finance lease income |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Energy Transition | Operating segments | Revenues from Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  |
Energy Transition | Operating segments | Brazeau penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  | 0
OM&A | 0 |  | 0
Energy Transition | Operating segments | Unrealized foreign exchange gain on commodity |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Energy Transition | Operating segments | Fuel and purchased power related to Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 |  |
Energy Transition | Operating segments | Australian interest income |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 | 0 | 0
Energy Transition | Operating segments | ERP integration costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Energy Transition | Operating segments | Acquisition-related transaction and restructuring costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Energy Transition | Operating segments | Sundance A decommissioning cost reimbursement |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) | 9 |  |
Energy Transition | Operating segments | Insurance recovery |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  | 0 |
Energy Transition | Operating segments | Royalty onerous contract and contract termination penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  |  | 0
Energy Marketing | Operating segments |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 167 | 152 | 218
Fuel and purchased power | 0 | 0 | 0
Carbon compliance | 0 | 0 | 0
Gross margin | 167 | 152 | 218
OM&A | 36 |  | 35
Taxes, other than income taxes | 0 | 0 | 0
Net other operating loss (income) | 0 | 0 | 0
Adjusted EBITDA | 131 | 109 | 183
Energy Marketing | Operating segments | Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 168 | 220 | 160
Fuel and purchased power | 0 | 0 | 0
OM&A | 36 | 43 | 35
Net other operating loss (income) | 0 | 0 | 0
Energy Marketing | Operating segments | Unrealized mark-to-market (gain) loss |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 14 | 23 | 12
Energy Marketing | Operating segments | Realized gain (loss) on closed exchange positions |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (15) | (91) | 47
Energy Marketing | Operating segments | Decrease in finance lease receivable |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Energy Marketing | Operating segments | Finance lease income |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Energy Marketing | Operating segments | Revenues from Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  |
Energy Marketing | Operating segments | Brazeau penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  | 0
OM&A | 0 |  | 0
Energy Marketing | Operating segments | Unrealized foreign exchange gain on commodity |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | (1)
Energy Marketing | Operating segments | Fuel and purchased power related to Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 |  |
Energy Marketing | Operating segments | Australian interest income |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 | 0 | 0
Energy Marketing | Operating segments | ERP integration costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Energy Marketing | Operating segments | Acquisition-related transaction and restructuring costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | 0 |  |
Energy Marketing | Operating segments | Sundance A decommissioning cost reimbursement |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) | 0 |  |
Energy Marketing | Operating segments | Insurance recovery |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  | 0 |
Energy Marketing | Operating segments | Royalty onerous contract and contract termination penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  |  | 0
Corporate | Operating segments |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (34) | 1 | (2)
Fuel and purchased power | 0 | 1 | 3
Carbon compliance | (34) | 0 | (5)
Gross margin | 0 | 0 | 0
OM&A | 135 |  | 101
Taxes, other than income taxes | 1 | 1 | 1
Net other operating loss (income) | 0 | 0 | 0
Adjusted EBITDA | (136) | (116) | (102)
Corporate | Operating segments | Previously Reported |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | (34) | 1 | (2)
Fuel and purchased power | 0 | 1 | 3
OM&A | 173 | 115 | 101
Net other operating loss (income) | 0 | 0 | 0
Corporate | Operating segments | Unrealized mark-to-market (gain) loss |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Corporate | Operating segments | Realized gain (loss) on closed exchange positions |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Corporate | Operating segments | Decrease in finance lease receivable |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Corporate | Operating segments | Finance lease income |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Corporate | Operating segments | Revenues from Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  |
Corporate | Operating segments | Brazeau penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 |  | 0
OM&A | 0 |  | 0
Corporate | Operating segments | Unrealized foreign exchange gain on commodity |  |  |
Disclosure of operating segments [line items] |  |  |
Revenue | 0 | 0 | 0
Corporate | Operating segments | Fuel and purchased power related to Planned Divestitures |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 |  |
Corporate | Operating segments | Australian interest income |  |  |
Disclosure of operating segments [line items] |  |  |
Fuel and purchased power | 0 | 0 | 0
Corporate | Operating segments | ERP integration costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | (14) |  |
Corporate | Operating segments | Acquisition-related transaction and restructuring costs |  |  |
Disclosure of operating segments [line items] |  |  |
OM&A | (24) |  |
Corporate | Operating segments | Sundance A decommissioning cost reimbursement |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) | $ 0 |  |
Corporate | Operating segments | Insurance recovery |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  | $ 0 |
Corporate | Operating segments | Royalty onerous contract and contract termination penalties |  |  |
Disclosure of operating segments [line items] |  |  |
Net other operating loss (income) |  |  | $ 0

X
- Definition The amount of depreciation and amortisation expense. Depreciation and amortisation are the systematic allocations of depreciable amounts of assets over their useful lives. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 28 -Subparagraph e -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_28_e&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 23 -Subparagraph e -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_23_e&doctype=Standard -URIDate 2024-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2024-01-01 -Paragraph B13 -Subparagraph d -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B13_d&doctype=Appendix&subtype=B -URIDate 2024-03-27 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 102 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_102&doctype=Standard -URIDate 2024-03-27 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 99 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_99&doctype=Standard -URIDate 2024-03-27 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 104 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_104&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_DepreciationAndAmortisationExpense
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table. + References No definition available. + Details
Name: | ifrs-full_DisclosureOfOperatingSegmentsLineItems
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of finance income on the net investment in the finance lease. [Refer: Finance income; Net investment in finance lease] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 16 -IssueDate 2024-01-01 -Paragraph 90 -Subparagraph a -Clause ii -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=16&code=ifrs-tx-2024-en-r&anchor=para_90_a_ii&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_FinanceIncomeOnNetInvestmentInFinanceLease
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of exchange differences recognised in profit or loss that arise from foreign currency transactions, excluding those arising on financial instruments measured at fair value through profit or loss in accordance with IFRS 9. [Refer: At fair value [member]; Classes of financial instruments [domain]] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 21 -IssueDate 2024-01-01 -Paragraph 52 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=21&code=ifrs-tx-2024-en-r&anchor=para_52_a&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 35 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_35&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationRecognisedInProfitOrLoss
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The gain on disposals of non-current assets. [Refer: Non-current assets] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 112 -Subparagraph c -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_GainsOnDisposalsOfNoncurrentAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of revenue less cost of sales. [Refer: Cost of sales; Revenue] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 103 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_103&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_GrossProfit
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of impairment loss or reversal of impairment loss recognised in profit or loss. [Refer: Impairment loss recognised in profit or loss; Reversal of impairment loss recognised in profit or loss] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 99 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_99&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_ImpairmentLossReversalOfImpairmentLossRecognisedInProfitOrLoss
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of income or expense arising from interest. [Refer: Interest expense; Interest income] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 28 -Subparagraph e -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_28_e&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 23 -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_23&doctype=Standard -URIDate 2024-03-27 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 85 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_85&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_InterestRevenueExpense
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Adjustments to reconcile profit (loss) to net cash flow from (used in) operating activities that the entity does not separately disclose in the same statement or note. [Refer: Adjustments to reconcile profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 7 -IssueDate 2024-01-01 -Paragraph 20 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2024-en-r&anchor=para_20&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_OtherAdjustmentsToReconcileProfitLoss
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The profit (loss) before tax expense or income. [Refer: Profit (loss)] + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 28 -Subparagraph b -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_28_b&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 23 -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_23&doctype=Standard -URIDate 2024-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 5 -IssueDate 2024-01-01 -Paragraph 33 -Subparagraph b -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2024-en-r&anchor=para_33_b_i&doctype=Standard -URIDate 2024-03-27 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 103 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_103&doctype=Standard -URIDate 2024-03-27 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 102 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_102&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_ProfitLossBeforeTax
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The income arising in the course of an entity's ordinary activities. Income is increases in assets, or decreases in liabilities, that result in increases in equity, other than those relating to contributions from holders of equity claims. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 28 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_28_a&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 23 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_23_a&doctype=Standard -URIDate 2024-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 32 -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_32&doctype=Standard -URIDate 2024-03-27 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 33 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_33_a&doctype=Standard -URIDate 2024-03-27 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 34 -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_34&doctype=Standard -URIDate 2024-03-27 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 5 -IssueDate 2024-01-01 -Paragraph 33 -Subparagraph b -Clause i -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=5&code=ifrs-tx-2024-en-r&anchor=para_33_b_i&doctype=Standard -URIDate 2024-03-27 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2024-01-01 -Paragraph B12 -Subparagraph b -Clause v -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B12_b_v&doctype=Appendix&subtype=B -URIDate 2024-03-27 Reference 8: http://www.xbrl.org/2003/role/exampleRef -Name IFRS -Number 12 -IssueDate 2024-01-01 -Paragraph B10 -Subparagraph b -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B -URIDate 2024-03-27 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 82 -Subparagraph a -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_82_a&doctype=Standard -URIDate 2024-03-27 Reference 10: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 103 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_103&doctype=Standard -URIDate 2024-03-27 Reference 11: http://www.xbrl.org/2003/role/exampleRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 102 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_102&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_Revenue
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of income arising from interest. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 23 -Subparagraph c -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_23_c&doctype=Standard -URIDate 2024-03-27 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 8 -IssueDate 2024-01-01 -Paragraph 28 -Subparagraph e -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2024-en-r&anchor=para_28_e&doctype=Standard -URIDate 2024-03-27 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name IFRS -Number 12 -IssueDate 2024-01-01 -Paragraph B13 -Subparagraph e -URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2024-en-r&anchor=para_B13_e&doctype=Appendix&subtype=B -URIDate 2024-03-27 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 112 -Subparagraph c -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_112_c&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_RevenueFromInterest
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The entity's share of the profit (loss) of associates accounted for using the equity method. [Refer: Total for all associates [member]; Investments accounted for using equity method; Profit (loss)] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 85 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_85&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_ShareOfProfitLossOfAssociatesAccountedForUsingEquityMethod
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of tax expense exclusive of income tax expense. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2024-01-01 -Paragraph 85 -URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2024-en-r&anchor=para_85&doctype=Standard -URIDate 2024-03-27 + Details
Name: | ifrs-full_TaxExpenseOtherThanIncomeTaxExpense
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Adjusted Profit (Loss) Before Income Taxes And Depreciation and Amortization + References No definition available. + Details
Name: | tac_AdjustedProfitLossBeforeIncomeTaxesAndDepreciationAndAmortization
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Carbon Compliance Expense + References No definition available. + Details
Name: | tac_CarbonComplianceExpense
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fuel Expense And Cost Of Purchased Energy Sold + References No definition available. + Details
Name: | tac_FuelExpenseAndCostOfPurchasedEnergySold
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Operations, Maintenance, And Administrative Expense + References No definition available. + Details
Name: | tac_OperationsMaintenanceAndAdministrativeExpense
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_RestatementAxis=srt_ScenarioPreviouslyReportedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentConsolidationItemsAxis=ifrs-full_OperatingSegmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsUnrealizedMarkToMarketGainLossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RealizedGainsLossesOnClosedExchangePositionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsDecreaseInFinanceLeaseReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsFinanceLeaseIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsRevenueFromPlannedDivestituresMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsBrazeauPenaltyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsUnrealizedForeignExchangeLossOnCommodityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsFuelAndPurchasedPowerRelatedToPlannedDivestituresMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsAustralianInterestIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodERPImplementationCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodAcquisitionAndIntegrationCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsDecommissioningCostReimbursementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsInsuranceRecoveryMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RestatementAxis=tac_RevisionOfPriorPeriodReclassificationsAndAdjustmentsRoyaltyOnerousContractAndContractTerminationPenaltiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentConsolidationItemsAxis=ifrs-full_MaterialReconcilingItemsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfAssetsAxis=ifrs-full_InvestmentsAccountedForUsingEquityMethodMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentsAxis=tac_HydroMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentsAxis=tac_WindandSolarMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentsAxis=tac_GasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentsAxis=tac_EnergyTransitionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentsAxis=tac_EnergyMarketingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_SegmentsAxis=tac_CorporateAndOther1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |