XML 52 R71.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Decommissioning and Other Provisions (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2019
Other Provisions, Contingent Liabilities And Contingent Assets [Abstract] |
Change in decommissioning and other provision balances | The change in decommissioning and other provision balances is as follows:
| Decommissioning and restoration | Other | Total
Balance, Dec. 31, 2017 | 437 |  | 33 |  | 470 |
Liabilities incurred | 5 |  | 17 |  | 22 |
Liabilities settled | (31) |  | (10) |  | (41) |
Accretion | 24 |  | — |  | 24 |
Acquisition of liabilities (Big Level) | — |  | 8 |  | 8 |
Revisions in estimated cash flows | 2 |  | 3 |  | 5 |
Revisions in discount rates | (37) |  | — |  | (37) |
Reversals | — |  | (5) |  | (5) |
Change in foreign exchange rates | 7 |  | 3 |  | 10 |
Balance, Dec. 31, 2018 | 407 |  | 49 |  | 456 |
IFRS 16 transition adjustment | — |  | (2) |  | (2) |
Liabilities incurred | 7 |  | 7 |  | 14 |
Liabilities settled | (34) |  | (9) |  | (43) |
Accretion | 23 |  | — |  | 23 |
Acquisition of liabilities | 16 |  | 3 |  | 19 |
Disposition of liabilities | (23) |  | (9) |  | (32) |
Revisions in estimated cash flows(1) | 96 |  | 7 |  | 103 |
Revisions in discount rates | 16 |  | — |  | 16 |
Reversals | — |  | (1) |  | (1) |
Change in foreign exchange rates | (7) |  | — |  | (7) |
Balance, Dec. 31, 2019 | 501 |  | 45 |  | 546 |
(1) During 2019, the Corporation adjusted the Centralia mine decommissioning and restoration provision as management no longer believes that the fine coal recovery and reclamation work will occur as originally proposed. Refer to Note 3(A)(III) for further details. In addition, due to the changes in estimated useful lives, described in Note 3(A)(IV), the discount rates used for the Canadian coal and mining operations decommissioning provisions were changed. The use of a lower inflation rate decreased the corresponding liabilities.
| Decommissioning and restoration | Other | Total
Balance, Dec. 31, 2018 | 407 |  | 49 |  | 456 |
Current portion | 35 |  | 35 |  | 70 |
Non-current portion | 372 |  | 14 |  | 386 |
Balance, Dec. 31, 2019 | 501 |  | 45 |  | 546 |
Current portion | 36 |  | 22 |  | 58 |
Non-current portion | 465 |  | 23 |  | 488 |

X
- Definition The disclosure of other provisions. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 37 -IssueDate 2018-01-01 -Paragraph 84 -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2018-03-01&anchor=para_84&doctype=Standard -URIDate 2018-03-16 + Details
Name: | ifrs-full_DisclosureOfOtherProvisionsExplanatory
Namespace Prefix: | ifrs-full_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Other Provisions, Contingent Liabilities And Contingent Assets [Abstract] + References No definition available. + Details
Name: | tac_OtherProvisionsContingentLiabilitiesAndContingentAssetsAbstract
Namespace Prefix: | tac_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration