XML 209 R181.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Commitments and Contingencies - Commitments (Details) CAD in Millions, AUD in Millions, $ in Millions |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
Jul. 30, 2015 USD ($) | Dec. 31, 2017 CAD | Dec. 31, 2016 CAD | Dec. 31, 2015 CAD | Dec. 31, 2017 USD ($) | Dec. 31, 2017 AUD | Nov. 17, 2017 AUD
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Coal supply and mining agreements |  | CAD 608.0 |  |  |  |  |
Long-term service agreements |  | 280.0 |  |  |  |  |
Non-cancellable operating leases |  | 156.0 |  |  |  |  |
Growth |  | 27.0 |  |  |  |  |
TransAlta Energy Transition Bill | $ 55 | 36.0 |  |  |  |  |
Total |  | 1,229.0 |  |  |  |  |
Minimum operating lease payments recognised as expense |  | 7.0 | CAD 9.0 | CAD 9.0 |  |  |
Sublease payments received (amounts less than) |  | 1.0 | CAD 1.0 |  |  |  |
Commitment period for Energy Bill initiatives | 9 years |  |  |  |  |  |
Funded portion of Energy Bill commitment | $ |  |  |  |  | $ 28 |  |
Amount withheld under dispute | AUD |  |  |  |  |  | AUD 58.2 |
Amount withheld under dispute, tax | AUD |  |  |  |  |  | AUD 43.0 |
Pending litigation claim | AUD |  |  |  |  |  |  | AUD 54.1
Natural gas, transportation, and other purchase contracts |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 98.0 |  |  |  |  |
Transmission |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 24.0 |  |  |  |  |
2018 |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Coal supply and mining agreements |  | 155.0 |  |  |  |  |
Long-term service agreements |  | 108.0 |  |  |  |  |
Non-cancellable operating leases |  | 9.0 |  |  |  |  |
Growth |  | 27.0 |  |  |  |  |
TransAlta Energy Transition Bill |  | 6.0 |  |  |  |  |
Total |  | 362.0 |  |  |  |  |
2018 | Natural gas, transportation, and other purchase contracts |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 48.0 |  |  |  |  |
2018 | Transmission |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 9.0 |  |  |  |  |
2019 |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Coal supply and mining agreements |  | 159.0 |  |  |  |  |
Long-term service agreements |  | 50.0 |  |  |  |  |
Non-cancellable operating leases |  | 9.0 |  |  |  |  |
Growth |  | 0.0 |  |  |  |  |
TransAlta Energy Transition Bill |  | 6.0 |  |  |  |  |
Total |  | 237.0 |  |  |  |  |
2019 | Natural gas, transportation, and other purchase contracts |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 7.0 |  |  |  |  |
2019 | Transmission |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 6.0 |  |  |  |  |
2020 |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Coal supply and mining agreements |  | 161.0 |  |  |  |  |
Long-term service agreements |  | 41.0 |  |  |  |  |
Non-cancellable operating leases |  | 9.0 |  |  |  |  |
Growth |  | 0.0 |  |  |  |  |
TransAlta Energy Transition Bill |  | 6.0 |  |  |  |  |
Total |  | 228.0 |  |  |  |  |
2020 | Natural gas, transportation, and other purchase contracts |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 5.0 |  |  |  |  |
2020 | Transmission |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 6.0 |  |  |  |  |
2021 |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Coal supply and mining agreements |  | 23.0 |  |  |  |  |
Long-term service agreements |  | 31.0 |  |  |  |  |
Non-cancellable operating leases |  | 9.0 |  |  |  |  |
Growth |  | 0.0 |  |  |  |  |
TransAlta Energy Transition Bill |  | 6.0 |  |  |  |  |
Total |  | 77.0 |  |  |  |  |
2021 | Natural gas, transportation, and other purchase contracts |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 5.0 |  |  |  |  |
2021 | Transmission |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 3.0 |  |  |  |  |
2022 |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Coal supply and mining agreements |  | 14.0 |  |  |  |  |
Long-term service agreements |  | 15.0 |  |  |  |  |
Non-cancellable operating leases |  | 9.0 |  |  |  |  |
Growth |  | 0.0 |  |  |  |  |
TransAlta Energy Transition Bill |  | 6.0 |  |  |  |  |
Total |  | 48.0 |  |  |  |  |
2022 | Natural gas, transportation, and other purchase contracts |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 4.0 |  |  |  |  |
2022 | Transmission |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 0.0 |  |  |  |  |
2023 and thereafter |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Coal supply and mining agreements |  | 96.0 |  |  |  |  |
Long-term service agreements |  | 35.0 |  |  |  |  |
Non-cancellable operating leases |  | 111.0 |  |  |  |  |
Growth |  | 0.0 |  |  |  |  |
TransAlta Energy Transition Bill |  | 6.0 |  |  |  |  |
Total |  | 277.0 |  |  |  |  |
2023 and thereafter | Natural gas, transportation, and other purchase contracts |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 29.0 |  |  |  |  |
2023 and thereafter | Transmission |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Purchase obligations |  | 0.0 |  |  |  |  |
Line loss rule proceeding |  |  |  |  |  |  |
Disclosure of Commitments [Line Items] |  |  |  |  |  |  |
Estimated financial effect of contingent liabilities |  | 15.0 |  |  |  |  |
Provision for line loss rule proceeding |  | CAD 7.5 |  |  |  |  |

X
- Definition The amount of additional other provisions made. [Refer: Other provisions] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name IAS -Number 37 -IssueDate 2017-01-01 -Paragraph 84 -Subparagraph b -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=37&date=2017-03-01&anchor=para_84_b&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_AdditionalProvisionsOtherProvisions
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of capital commitments for which the entity has entered into a contract. [Refer: Capital commitments] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 112 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_112_c&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_ContractualCapitalCommitments
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount of income from subleasing right-of-use assets. Sublease is a transaction for which an underlying asset is re-leased by a lessee (‘intermediate lessor’) to a third party, and the lease (‘head lease’) between the head lessor and lessee remains in effect. [Refer: Right-of-use assets] + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Note Effective 2019-01-01 -Name IFRS -Number 16 -IssueDate 2017-01-01 -Paragraph 53 -Subparagraph f -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=16&date=2017-03-01&anchor=para_53_f&doctype=Standard -URIDate 2017-03-09 + Details
Name: | ifrs-full_IncomeFromSubleasingRightofuseAssets
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of future minimum lease payments payable under non-cancellable operating leases. Minimum lease payments are payments over the lease term that the lessee is or can be required to make, excluding contingent rent, costs for services and taxes to be paid by, and reimbursed to, the lessor, together with: (a) for a lessee, any amounts guaranteed by the lessee or by a party related to the lessee; or (b) for a lessor, any residual value guaranteed to the lessor by: (i) the lessee; (ii) a party related to the lessee; or (iii) a third party unrelated to the lessor that is financially capable of discharging the obligations under the guarantee. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Note Expiry date 2019-01-01 -Name IAS -Number 17 -IssueDate 2017-01-01 -Paragraph 35 -Subparagraph a -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=17&date=2017-03-02&anchor=para_35_a&doctype=Standard&book=B -URIDate 2017-03-09 + Details
Name: | ifrs-full_MinimumLeasePaymentsPayableUnderNoncancellableOperatingLease
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The portion of operating lease payments that the lessee is or can be required to make, excluding contingent rent, costs for services and taxes to be paid by, and reimbursed to, the lessor, together with any amounts guaranteed by the lessee or by a party related to the lessee recognised as an expense. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Note Expiry date 2019-01-01 -Name IAS -Number 17 -IssueDate 2017-01-01 -Paragraph 35 -Subparagraph c -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=17&date=2017-03-02&anchor=para_35_c&doctype=Standard&book=B -URIDate 2017-03-09 + Details
Name: | ifrs-full_MinimumOperatingLeasePayments
Namespace Prefix: | ifrs-full_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount Withheld Under Litigation Dispute + References No definition available. + Details
Name: | tac_AmountWithheldUnderLitigationDispute
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount Withheld Under Litigation Dispute, Tax + References No definition available. + Details
Name: | tac_AmountWithheldUnderLitigationDisputeTax
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Coal Supply and Mining Obligation + References No definition available. + Details
Name: | tac_CoalSupplyandMiningObligation
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Commitment Period for Energy Bill Initiatives + References No definition available. + Details
Name: | tac_CommitmentPeriodforEnergyBillInitiatives
Namespace Prefix: | tac_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Commitment for Energy Bill Initiatives + References No definition available. + Details
Name: | tac_CommitmentforEnergyBillInitiatives
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contingent Liabilities, Maximum Exposure + References No definition available. + Details
Name: | tac_ContingentLiabilitiesMaximumExposure
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Contractual Obligations1 + References No definition available. + Details
Name: | tac_ContractualObligations1
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition [Line Items] for Disclosure of Commitments [Table] + References No definition available. + Details
Name: | tac_DisclosureofCommitmentsLineItems
Namespace Prefix: | tac_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Long-term Service Obligation + References No definition available. + Details
Name: | tac_LongtermServiceObligation
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Noncurrent Prepayments for Energy Bill Commitments + References No definition available. + Details
Name: | tac_NoncurrentPrepaymentsforEnergyBillCommittments
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Pending litigation claim + References No definition available. + Details
Name: | tac_Pendinglitigationclaim
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Purchase Obligations1 + References No definition available. + Details
Name: | tac_PurchaseObligations1
Namespace Prefix: | tac_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | tac_PurchaseObligationItemAxis=tac_NaturalGasTransportationandOtherProductsandServicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | tac_PurchaseObligationItemAxis=tac_TransmissionNetworkCapacityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_NotLaterThanOneYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanOneYearAndNotLaterThanTwoYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanTwoYearsAndNotLaterThanThreeYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanThreeYearsAndNotLaterThanFourYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanFourYearsAndNotLaterThanFiveYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_MaturityAxis=ifrs-full_LaterThanFiveYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | ifrs-full_ClassesOfProvisionsAxis=ifrs-full_LegalProceedingsProvisionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |