Areas of Judgment and Estimation Uncertainty	12 Months Ended
Dec. 31, 2023
Areas of Judgment and Estimation Uncertainty [Abstract]
Areas of Judgment and Estimation Uncertainty	4. Areas of Judgment and Estimation Uncertainty In preparing our consolidated financial statements, we make judgments in applying our accounting policies. The judgments that have the most significant effect on the amounts recognized in our financial statements are outlined below. In addition, we make assumptions about the future in deriving estimates used in preparing our consolidated financial statements. We have outlined information below about assumptions and other sources of estimation uncertainty as at December 31, 2023 that have a risk of resulting in a material adjustment to the carrying amounts of assets and liabilities within the next year. a) Areas of Judgment Assessment of Impairment and Impairment Reversal Indicators Judgment is required in assessing whether certain factors would be considered an indicator of impairment or impairment reversal. We consider both internal and external information to determine whether there is an indicator of impairment or impairment reversal present and, accordingly, whether impairment testing is required. The information we consider in assessing whether there is an indicator of impairment or impairment reversal includes, but is not limited to, market transactions for similar assets, commodity prices, treatment charges, zinc premiums, discount rates, foreign exchange rates, our market capitalization, reserves and resources, mine plans, operating plans and operating results. As a result of the strengthening of the Canadian dollar against the U.S. dollar affecting the Canadian dollar equivalent of our expected consideration to be received in the sale of the steelmaking coal business transactions (Note 6(a)), we performed an impairment test for our steelmaking coal group of CGUs (Note 9(a)) at December 31, 2023. In the fourth quarter of 2022, as a result of increased costs and operating challenges at our Trail CGU, we performed an impairment test for our Trail CGU (Note 9(b) and (d)). Property, Plant and Equipment – Determination of Available for Use Date Judgment is required in determining the date that property, plant and equipment is available for use. An asset is available for use when it is in the location and condition necessary to operate in the manner intended by management. QB2 consists of property, plant and equipment that become available for use at different dates. When assessing when these assets are available for use, we consider several factors, the most significant of which are the status of asset commissioning and whether the assets are capable of operating near design capacity to ensure a reliable and consistent throughput rate to produce the expected quantity of outputs. The majority of the assets related to QB2 became available for use in December of 2023. Joint Arrangements We are a party to a number of arrangements over which we do not have control. Judgment is required in determining whether joint control over these arrangements exists and, if so, which parties have joint control and whether each arrangement is a joint venture or a joint operation. In assessing whether we have joint control, we analyze the activities of each arrangement and determine which activities most significantly affect the returns of the arrangement over its life. These activities are determined to be the relevant activities of the arrangement. If unanimous consent is required over the decisions about the relevant activities, the parties whose consent is required would have joint control over the arrangement. The judgments around which activities are considered the relevant activities of the arrangement are subject to analysis by each of the parties to the arrangement and may be interpreted differently. When performing this assessment, we generally consider decisions about activities such as managing the asset while it is being designed, developed and constructed, during its operating life and during the closure period. We may also consider other activities, including the approval of budgets, expansion and disposition of assets, financing, significant operating and capital expenditures, appointment of key management personnel, representation on the board of directors and other items. When circumstances or contractual terms change, we reassess the control group and the relevant activities of the arrangement. 4. Areas of Judgment and Estimation Uncertainty (continued) If we have joint control over the arrangement, an assessment of whether the arrangement is a joint venture or a joint operation is required. This assessment is based on whether we have rights to the assets, and obligations for the liabilities, relating to the arrangement or whether we have rights to the net assets of the arrangement. In making this determination, we review the legal form of the arrangement, the terms of the contractual arrangement and other facts and circumstances. In a situation where the legal form and the terms of the contractual arrangement do not give us rights to the assets and obligations for the liabilities, an assessment of other facts and circumstances is required, including whether the activities of the arrangement are primarily designed for the provision of output to the parties and whether the parties are substantially the only source of cash flows contributing to the arrangement. The consideration of other facts and circumstances may result in the conclusion that a joint arrangement is a joint operation. This conclusion requires judgment and is specific to each arrangement. Other facts and circumstances have led us to conclude that Antamina, NewRange and San Nicolás are joint operations for the purposes of our consolidated financial statements. The other facts and circumstances considered for these arrangements include the provision of output to the parties of the joint arrangements and the funding obligations. For Antamina, NewRange and San Nicolás, we take our share of the output from the assets directly over the life of the arrangement. We have concluded that this gives us direct rights to the assets and obligations for the liabilities of these arrangements proportionate to our ownership interests. Streaming Transactions When we enter into a long-term streaming arrangement linked to production at specific operations, judgment is required in assessing the appropriate accounting treatment for the transaction on the closing date and in future periods. We consider the specific terms of each arrangement to determine whether we have disposed of an interest in the reserves and resources of the respective operation or executed some other form of arrangement. This assessment considers what the counterparty is entitled to and the associated risks and rewards attributable to them over the life of the operation. These include the contractual terms related to the total production over the life of the arrangement as compared to the expected production over the life of the mine, the percentage being sold, the percentage of payable metals produced, the commodity price referred to in the ongoing payment and any guarantee relating to the upfront payment if production ceases. For our silver and gold streaming arrangements at Antamina and Carmen de Andacollo, respectively, there is no guarantee associated with the upfront payment. We have concluded that control of the rights to the silver and gold mineral interests were transferred to the buyers when the contracts came into effect. Therefore, we consider these arrangements a disposition of a mineral interest. Based on our judgment, control of the interest in the reserves and resources transferred to the buyer when the contracts were executed. At that time, we recognized the amount of the gain related to the disposition of the reserves and resources, as we had the right to payment, the customer was entitled to the commodities, the buyer had no recourse in requiring Teck to mine the product, and the buyer had significant risks and rewards of ownership of the reserves and resources. We recognize the amount of consideration related to refining, mining and delivery services as the work is performed. Deferred Tax Assets and Liabilities Judgment is required in assessing whether deferred tax assets and certain deferred tax liabilities are recognized on the balance sheet and what tax rate is expected to be applied in the year when the related temporary differences reverse. We also evaluate the recoverability of deferred tax assets based on an assessment of our ability to use the underlying future tax deductions before they expire against future taxable profits or capital gains. Deferred tax liabilities arising from temporary differences on investments in subsidiaries, joint ventures and associates are recognized unless the reversal of the temporary differences is not expected to occur in the foreseeable future and can be controlled. Judgment is also required on the application of income tax legislation. These judgments are subject to risk and uncertainty and could result in an adjustment to the deferred tax provision and a corresponding credit or charge to profit (loss). 4. Areas of Judgment and Estimation Uncertainty (continued) Assets Held for Sale Judgment is required in assessing whether certain assets are considered as held for sale as at December 31, 2023. For non-current assets and disposal groups to be considered as held for sale, the asset or disposal group must be available for immediate disposal, by sale or otherwise, in its present condition subject only to terms that are usual and customary for sales of such assets or disposal groups, and its sale must be highly probable. Exercising judgment includes considering the likelihood of obtaining requisite regulatory, stakeholder and political approvals. In the fourth quarter of 2023, we announced our agreement to sell our interest in our steelmaking coal business, referred to as Elk Valley Resources (EVR), through a sale of a majority stake to Glencore plc (Glencore) and a sale of minority stakes to Nippon Steel Corporation (NSC) and POSCO. The NSC and POSCO portions of the transaction closed on January 3, 2024 (Note 6(a)). Closing of the sale of the majority interest in EVR to Glencore remains subject to receipt of competition approvals in several jurisdictions and approval under the Investment Canada Act. The timing and outcome of these processes is not known with sufficient certainty and as such, we are not in a position to conclude that receipt of the required approvals, and resulting closing of the transaction, is highly probable. Therefore, we have determined that our steelmaking coal business did not meet the criteria to be classified as held for sale at December 31, 2023. As at December 31, 2022, we determined that the Fort Hills disposal group; the Quintette disposal group; the Mesaba property, plant and equipment assets; and the San Nicolás property, plant and equipment assets were considered as held for sale (Note 5). b) Sources of Estimation Uncertainty Impairment Testing For the annual goodwill impairment testing for our steelmaking coal group of CGUs, we estimated its recoverable amount based on consideration expected to be received from the sale transactions (Note 6(a)). This includes the present value of the agreed-upon cash proceeds from Glencore and NSC, plus the expected discounted cash flows from the steelmaking coal business until closing of the Glencore transaction. The most significant assumption is the U.S. dollar to Canadian dollar foreign exchange rate, which is applied to both the cash receipts and the cash flows until closing. Other significant assumptions include the steelmaking coal price, sales volumes and operating costs. For other impairment testing required, discounted cash flow models are used to determine the recoverable amount of respective CGUs. These models are prepared internally or with assistance from third-party advisors when required. When relevant market transactions for comparable assets are available, these are considered in determining the recoverable amount of assets. Significant assumptions used in preparing the discounted cash flow model for our Quebrada Blanca CGU goodwill impairment test include commodity prices, reserves and resources, sales volumes, operating costs, capital expenditures, discount rate and the fair value per pound of copper equivalent used in the determination of the in situ value. Significant assumptions used in preparing the discounted cash flow model for our Trail CGU impairment test in 2022 include zinc prices, smelter production, operating costs, capital expenditures, treatment charges, zinc premiums, discount rate and foreign exchange rates. Note 9(d) outlines the significant inputs used when performing goodwill and other asset impairment testing. These inputs are based on management’s best estimates of what an independent market participant would consider appropriate. Changes in these inputs may alter the results of impairment testing, the amount of the impairment charges or reversals recorded in the statement of income (loss) and the resulting carrying values of assets. 4. Areas of Judgment and Estimation Uncertainty (continued) Estimated Recoverable Reserves and Resources Mineral reserve and resource estimates are based on various assumptions relating to operating matters as set forth in National Instrument 43-101, Standards of Disclosure for Mineral Projects. Assumptions used include production costs, mining and processing recoveries, cut-off grades, sales volumes, long-term commodity prices, exchange rates, inflation rates, tax and royalty rates and capital costs. Cost estimates are based on prefeasibility or feasibility study estimates or operating history. Estimates are prepared by or under the supervision of appropriately qualified persons, but will be affected by forecasted commodity prices, inflation rates, exchange rates, capital and production costs and recoveries, among other factors. Estimated recoverable reserves and resources are used in performing impairment testing, to determine the depreciation of property, plant and equipment at operating mine sites, in accounting for capitalized production stripping costs and also in forecasting the timing of settlement of decommissioning and restoration costs. Changes in reserve and resource estimates are most significant to estimating the recoverable amount in impairment tests. Decommissioning and Restoration Provisions Decommissioning and restoration provisions (DRPs) are based on future cost estimates using information available at the balance sheet date that are developed by management’s experts (Note 25(a)). DRPs represent the present value of estimated costs of future decommissioning and other site restoration activities, including costs associated with the management of water and water quality in and around each closed site. DRPs are adjusted at each reporting period for changes to factors such as the expected amount of cash flows required to discharge the liability, the timing of such cash flows and the credit-adjusted discount rate. DRPs require significant estimates and assumptions, including the requirements of the relevant legal and regulatory framework and the timing, extent and costs of required decommissioning and restoration activities. Our estimates of the costs associated with the management of water and water quality in and around each closed site include assumptions with respect to the volume and location of water to be treated, the methods used to treat the water and the related water treatment costs. To the extent the actual costs differ from these estimates, adjustments will be recorded and the statement of income (loss) may be affected. Provision for Income Taxes We calculate current and deferred tax provisions for each of the jurisdictions in which we operate. Actual amounts of income tax expense are not final until tax returns are filed and accepted by the relevant authorities. This occurs subsequent to the issuance of our financial statements and the final determination of actual amounts may not be completed for a number of years. Therefore, profit (loss) in subsequent periods will be affected by the amount that estimates differ from the final tax assessment. Deferred Tax Assets and Liabilities Assumptions about the generation of future taxable profits and repatriation of retained earnings depend on management’s estimates of future production and sales volumes, commodity prices, reserves and resources, operating costs, decommissioning and restoration costs, capital expenditures, dividends and other capital management transactions. These estimates could result in an adjustment to the deferred tax provision and a corresponding adjustment to profit (loss).

In preparing our consolidated financial statements, we make judgments in applying our accounting policies. The judgments that have the most significant effect on the amounts recognized in our financial statements are outlined below. In addition, we make assumptions about the future in deriving estimates used in preparing our consolidated financial statements. We have outlined information below about assumptions and other sources of estimation uncertainty as at December 31, 2023 that have a risk of resulting in a material adjustment to the carrying amounts of assets and liabilities within the next year.

Judgment is required in assessing whether certain factors would be considered an indicator of impairment or impairment reversal. We consider both internal and external information to determine whether there is an indicator of impairment or impairment reversal present and, accordingly, whether impairment testing is required. The information we consider in assessing whether there is an indicator of impairment or impairment reversal includes, but is not limited to, market transactions for similar assets, commodity prices, treatment charges, zinc premiums, discount rates, foreign exchange rates, our market capitalization, reserves and resources, mine plans, operating plans and operating results.

QB2 consists of property, plant and equipment that become available for use at different dates. When assessing when these assets are available for use, we consider several factors, the most significant of which are the status of asset commissioning and whether the assets are capable of operating near design capacity to ensure a reliable and consistent throughput rate to produce the expected quantity of outputs. The majority of the assets related to QB2 became available for use in December of 2023.

We are a party to a number of arrangements over which we do not have control. Judgment is required in determining whether joint control over these arrangements exists and, if so, which parties have joint control and whether each arrangement is a joint venture or a joint operation. In assessing whether we have joint control, we analyze the activities of each arrangement and determine which activities most significantly affect the returns of the arrangement over its life. These activities are determined to be the relevant activities of the arrangement. If unanimous consent is required over the decisions about the relevant activities, the parties whose consent is required would have joint control over the arrangement. The judgments around which activities are considered the relevant activities of the arrangement are subject to analysis by each of the parties to the arrangement and may be interpreted differently. When performing this assessment, we generally consider decisions about activities such as managing the asset while it is being designed, developed and constructed, during its operating life and during the closure period. We may also consider other activities, including the approval of budgets, expansion and disposition of assets, financing, significant operating and capital expenditures, appointment of key management personnel, representation on the board of directors and other items. When circumstances or contractual terms change, we reassess the control group and the relevant activities of the arrangement.

If we have joint control over the arrangement, an assessment of whether the arrangement is a joint venture or a joint operation is required. This assessment is based on whether we have rights to the assets, and obligations for the liabilities, relating to the arrangement or whether we have rights to the net assets of the arrangement. In making this determination, we review the legal form of the arrangement, the terms of the contractual arrangement and other facts and circumstances. In a situation where the legal form and the terms of the contractual arrangement do not give us rights to the assets and obligations for the liabilities, an assessment of other facts and circumstances is required, including whether the activities of the arrangement are primarily designed for the provision of output to the parties and whether the parties are substantially the only source of cash flows contributing to the arrangement. The consideration of other facts and circumstances may result in the conclusion that a joint arrangement is a joint operation. This conclusion requires judgment and is specific to each arrangement. Other facts and circumstances have led us to conclude that Antamina, NewRange and San Nicolás are joint operations for the purposes of our consolidated financial statements. The other facts and circumstances considered for these arrangements include the provision of output to the parties of the joint arrangements and the funding obligations. For Antamina, NewRange and San Nicolás, we take our share of the output from the assets directly over the life of the arrangement. We have concluded that this gives us direct rights to the assets and obligations for the liabilities of these arrangements proportionate to our ownership interests.

When we enter into a long-term streaming arrangement linked to production at specific operations, judgment is required in assessing the appropriate accounting treatment for the transaction on the closing date and in future periods. We consider the specific terms of each arrangement to determine whether we have disposed of an interest in the reserves and resources of the respective operation or executed some other form of arrangement. This assessment considers what the counterparty is entitled to and the associated risks and rewards attributable to them over the life of the operation. These include the contractual terms related to the total production over the life of the arrangement as compared to the expected production over the life of the mine, the percentage being sold, the percentage of payable metals produced, the commodity price referred to in the ongoing payment and any guarantee relating to the upfront payment if production ceases.

For our silver and gold streaming arrangements at Antamina and Carmen de Andacollo, respectively, there is no guarantee associated with the upfront payment. We have concluded that control of the rights to the silver and gold mineral interests were transferred to the buyers when the contracts came into effect. Therefore, we consider these arrangements a disposition of a mineral interest.

Based on our judgment, control of the interest in the reserves and resources transferred to the buyer when the contracts were executed. At that time, we recognized the amount of the gain related to the disposition of the reserves and resources, as we had the right to payment, the customer was entitled to the commodities, the buyer had no recourse in requiring Teck to mine the product, and the buyer had significant risks and rewards of ownership of the reserves and resources.

Judgment is required in assessing whether deferred tax assets and certain deferred tax liabilities are recognized on the balance sheet and what tax rate is expected to be applied in the year when the related temporary differences reverse. We also evaluate the recoverability of deferred tax assets based on an assessment of our ability to use the underlying future tax deductions before they expire against future taxable profits or capital gains. Deferred tax liabilities arising from temporary differences on investments in subsidiaries, joint ventures and associates are recognized unless the reversal of the temporary differences is not expected to occur in the foreseeable future and can be controlled. Judgment is also required on the application of income tax legislation. These judgments are subject to risk and uncertainty and could result in an adjustment to the deferred tax provision and a corresponding credit or charge to profit (loss).

Judgment is required in assessing whether certain assets are considered as held for sale as at December 31, 2023. For non-current assets and disposal groups to be considered as held for sale, the asset or disposal group must be available for immediate disposal, by sale or otherwise, in its present condition subject only to terms that are usual and customary for sales of such assets or disposal groups, and its sale must be highly probable. Exercising judgment includes considering the likelihood of obtaining requisite regulatory, stakeholder and political approvals.

In the fourth quarter of 2023, we announced our agreement to sell our interest in our steelmaking coal business, referred to as Elk Valley Resources (EVR), through a sale of a majority stake to Glencore plc (Glencore) and a sale of minority stakes to Nippon Steel Corporation (NSC) and POSCO. The NSC and POSCO portions of the transaction closed on January 3, 2024 (Note 6(a)). Closing of the sale of the majority interest in EVR to Glencore remains subject to receipt of competition approvals in several jurisdictions and approval under the Investment Canada Act. The timing and outcome of these processes is not known with sufficient certainty and as such, we are not in a position to conclude that receipt of the required approvals, and resulting closing of the transaction, is highly probable. Therefore, we have determined that our steelmaking coal business did not meet the criteria to be classified as held for sale at December 31, 2023.

For the annual goodwill impairment testing for our steelmaking coal group of CGUs, we estimated its recoverable amount based on consideration expected to be received from the sale transactions (Note 6(a)). This includes the present value of the agreed-upon cash proceeds from Glencore and NSC, plus the expected discounted cash flows from the steelmaking coal business until closing of the Glencore transaction. The most significant assumption is the U.S. dollar to Canadian dollar foreign exchange rate, which is applied to both the cash receipts and the cash flows until closing. Other significant assumptions include the steelmaking coal price, sales volumes and operating costs.

For other impairment testing required, discounted cash flow models are used to determine the recoverable amount of respective CGUs. These models are prepared internally or with assistance from third-party advisors when required. When relevant market transactions for comparable assets are available, these are considered in determining the recoverable amount of assets.

Note 9(d) outlines the significant inputs used when performing goodwill and other asset impairment testing. These inputs are based on management’s best estimates of what an independent market participant would consider appropriate. Changes in these inputs may alter the results of impairment testing, the amount of the impairment charges or reversals recorded in the statement of income (loss) and the resulting carrying values of assets.

Mineral reserve and resource estimates are based on various assumptions relating to operating matters as set forth in National Instrument 43-101, Standards of Disclosure for Mineral Projects. Assumptions used include production costs, mining and processing recoveries, cut-off grades, sales volumes, long-term commodity prices, exchange rates, inflation rates, tax and royalty rates and capital costs. Cost estimates are based on prefeasibility or feasibility study estimates or operating history. Estimates are prepared by or under the supervision of appropriately qualified persons, but will be affected by forecasted commodity prices, inflation rates, exchange rates, capital and production costs and recoveries, among other factors. Estimated recoverable reserves and resources are used in performing impairment testing, to determine the depreciation of property, plant and equipment at operating mine sites, in accounting for capitalized production stripping costs and also in forecasting the timing of settlement of decommissioning and restoration costs. Changes in reserve and resource estimates are most significant to estimating the recoverable amount in impairment tests.

Decommissioning and restoration provisions (DRPs) are based on future cost estimates using information available at the balance sheet date that are developed by management’s experts (Note 25(a)). DRPs represent the present value of estimated costs of future decommissioning and other site restoration activities, including costs associated with the management of water and water quality in and around each closed site. DRPs are adjusted at each reporting period for changes to factors such as the expected amount of cash flows required to discharge the liability, the timing of such cash flows and the credit-adjusted discount rate. DRPs require significant estimates and assumptions, including the requirements of the relevant legal and regulatory framework and the timing, extent and costs of required decommissioning and restoration activities. Our estimates of the costs associated with the management of water and water quality in and around each closed site include assumptions with respect to the volume and location of water to be treated, the methods used to treat the water and the related water treatment costs. To the extent the actual costs differ from these estimates, adjustments will be recorded and the statement of income (loss) may be affected.

We calculate current and deferred tax provisions for each of the jurisdictions in which we operate. Actual amounts of income tax expense are not final until tax returns are filed and accepted by the relevant authorities. This occurs subsequent to the issuance of our financial statements and the final determination of actual amounts may not be completed for a number of years. Therefore, profit (loss) in subsequent periods will be affected by the amount that estimates differ from the final tax assessment.

Assumptions about the generation of future taxable profits and repatriation of retained earnings depend on management’s estimates of future production and sales volumes, commodity prices, reserves and resources, operating costs, decommissioning and restoration costs, capital expenditures, dividends and other capital management transactions. These estimates could result in an adjustment to the deferred tax provision and a corresponding adjustment to profit (loss).