Cameco (CCJ) 40-F 19 Mar 21 2020 FY Annual report (Canada) Financial data

Document and Entity Information

Document and Entity Information	12 Months Ended
	Dec. 31, 2020shares
Document And Entity Information [Abstract]
Document Type	40-F
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	Cameco Corporation
Entity Central Index Key	0001009001
Entity Address, Address Line One	2121 – 11th Street West
Entity Address City or Town	Saskatoon
Entity Address State Or Province	SK
Entity Address, Postal Zip Code	S7M 1J3
Entity Address Country	CA
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding	396,262,741
Entity Emerging Growth Company	false
Entity Interactive Data Current	Yes

Consolidated statements of earn

Consolidated statements of earnings - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Consolidated statements of earnings [Abstract]
Revenue from products and services	$ 1,800,073	$ 1,862,925
Cost of products and services sold	1,484,962	1,345,551
Depreciation and amortization	208,662	275,749
Cost of sales	1,693,624	1,621,300
Gross profit	106,449	241,625
Administration	145,344	124,869
Exploration	10,873	13,686
Research and development	3,965	6,058
Other operating expense	23,921	2,732
Loss on disposal of assets	1,072	1,869
Earnings (loss) from operations	(78,726)	92,411
Finance costs	(96,133)	(98,622)
Gain (loss) on derivatives	36,577	32,269
Finance income	10,835	29,760
Share of earnings from equity-accounted investee	36,476	45,360
Other income (expense)	51,440	33,840
Earnings (loss) before income taxes	(39,531)	135,018
Income tax expense (recovery)	13,666	61,077
Net earnings (loss)	(53,197)	73,941
Net earnings (loss) attributable to:
Equity holders	(53,169)	74,000
Non-controlling interest	(28)	(59)
Profit (loss)	$ (53,197)	$ 73,941
Earnings per common share attributable to equity holders:
Basic	$ (0.13)	$ 0.19
Diluted	$ (0.13)	$ 0.19

Consolidated statements of comp

Consolidated statements of comprehensive income - CAD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Consolidated statements of comprehensive income [Abstract]
Profit (loss)		$ (53,197)	$ 73,941
Items that will not be reclassified to net earnings:
Remeasurements of defined benefit liability	[1]	(4,959)	(8,112)
Equity investments at FVOCI - net change in fair value	[2]	16,986	(4,044)
Equity instruments at FVOCI - net change in fair value - equity-accounted investee		(39)	(709)
Items that are or may be reclassified to net earnings:
Exchange differences on translation of foreign operations		26,807	(27,888)
Other comprehensive loss, net of taxes		38,795	(40,753)
Total comprehensive income (loss)		(14,402)	33,188
Other comprehensive income (loss) attributable to:
Equity holders		38,799	(40,740)
Non-controlling interest		(4)	(13)
Other comprehensive loss for the year		38,795	(40,753)
Total comprehensive income (loss) attributable to:
Equity holders		(14,370)	33,260
Non-controlling interest		(32)	(72)
Total comprehensive income (loss) for the year		(14,402)	33,188
Income tax on remeasurement of defined benefit liability		1,463	2,301
Income tax on equity investments at FVOCI - net change in fair value		$ (2,469)	$ 453
[1]	Net of tax ( 2020 - $ 1,463 ; 2019 - $ 2,301 )
[2]	Net of tax ( 2020 - $( 2,469 ) ; 2019 - $ 453 )

Consolidated statements of fina

Consolidated statements of financial position - CAD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 918,382	$ 1,062,431
Short-term investments	24,985	0
Accounts receivable	204,980	328,044
Current tax assets	8,184	3,667
Inventories	680,369	320,770
Supplies and prepaid expenses	89,428	85,502
Current portion of long-term receivables, investments and other	18,716	6,564
Total current assets	1,945,044	1,806,978
Property, plant and equipment	3,771,557	3,720,672
Intangible assets	55,822	60,410
Long-term receivables, investments and other	652,042	630,131
Investment in equity-accounted investee	219,688	252,681
Deferred tax assets	936,678	956,376
Total non-current assets	5,635,787	5,620,270
Total assets	7,580,831	7,427,248
Current liabilities
Accounts payable and accrued liabilities	233,649	181,799
Current tax liabilities	1,480	6,290
Current portion of other liabilities	26,119	33,073
Current portion of provisions	42,535	56,248
Total current liabilities	303,783	277,410
Long-term debt	995,541	996,718
Other liabilities	166,559	153,927
Provisions	1,156,387	1,004,230
Deferred tax liabilities	0	0
Total non-current liabilities	2,318,487	2,154,875
Shareholders' equity
Share capital	1,869,710	1,862,749
Contributed surplus	237,358	234,681
Retained earnings	2,735,830	2,825,596
Other components of equity	115,457	71,699
Total shareholders' equity attributable to equity holders	4,958,355	4,994,725
Non-controlling interest	206	238
Total shareholders' equity	4,958,561	4,994,963
Total liabilities and shareholders' equity	$ 7,580,831	$ 7,427,248

Consolidated statements of chan

Consolidated statements of changes in equity - CAD ($) $ in Thousands	Total	Share capital	Contributed surplus	Retained earnings	Foreign currency translation	Equity investments at FVOCI	Attributable to equity holders	Non-controling interest
Balance beginning period at Dec. 31, 2018	$ 4,993,592	$ 1,862,652	$ 234,982	$ 2,791,321	$ 104,989	$ (662)	$ 4,993,282	$ 310
Profit (loss)	73,941	0	0	74,000	0	0	74,000	(59)
Other comprehensive income (loss)	(40,753)	0	0	(8,112)	(27,875)	(4,753)	(40,740)	(13)
Total comprehensive income (loss) for the year	33,188	0	0	65,888	(27,875)	(4,753)	33,260	(72)
Share-based compensation	14,342	0	14,342	0	0	0	14,342	0
Stock options exercised	81	97	(16)	0	0	0	81	0
Restricted and performance share units released	(6,258)	0	(6,258)	0	0	0	(6,258)	0
Modification of share-based arrangement	(8,369)	0	(8,369)	0	0	0	(8,369)	0
Dividends	(31,613)	0	0	(31,613)	0	0	(31,613)	0
Balance ending period at Dec. 31, 2019	4,994,963	1,862,749	234,681	2,825,596	77,114	(5,415)	4,994,725	238
Profit (loss)	(53,197)	0	0	(53,169)	0	0	(53,169)	(28)
Other comprehensive income (loss)	38,795	0	0	(4,959)	26,811	16,947	38,799	(4)
Total comprehensive income (loss) for the year	(14,402)	0	0	(58,128)	26,811	16,947	(14,370)	(32)
Share-based compensation	6,564	0	6,564	0	0	0	6,564	0
Stock options exercised	5,375	6,961	(1,586)	0	0	0	5,375	0
Restricted and performance share units released	(2,301)	0	(2,301)	0	0	0	(2,301)	0
Dividends	(31,638)	0	0	(31,638)	0	0	(31,638)	0
Balance ending period at Dec. 31, 2020	$ 4,958,561	$ 1,869,710	$ 237,358	$ 2,735,830	$ 103,925	$ 11,532	$ 4,958,355	$ 206

Consolidated statements of cash

Consolidated statements of cash flows - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Profit (loss)	$ (53,197)	$ 73,941
Adjustments for:
Depreciation and amortization	208,662	275,749
Deferred charges	(2,945)	(13,013)
Unrealized loss (gain) on derivatives	(42,892)	(55,048)
Share-based compensation	6,564	14,342
Loss on disposal of assets	1,072	1,869
Finance costs	96,133	98,622
Finance income	(10,835)	(29,760)
Share of earnings from equity-accounted investee	(36,476)	(45,360)
Other expense (income)	(13,891)	18,961
Other operating expense	23,921	2,732
Income tax expense (recovery)	13,666	61,077
Interest received	9,994	30,944
Income taxes paid	(4,374)	(18,589)
Dividends from equity-accounted investee	54,404	14,079
Other operating items	(192,917)	96,478
Net cash provided by operations	56,889	527,024
Investing activities
Additions to property, plant and equipment	(77,462)	(75,211)
Decrease (increase) in short-term investments	(24,985)	391,025
Decrease in long-term receivables, investments and other	907	120,913
Proceeds from sale of property, plant and equipment	511	679
Net cash provided by (used in) investing	(101,029)	437,406
Financing activities
Increase in long-term debt	397,539	0
Decrease in long-term debt	(400,000)	(500,000)
Interest paid	(65,547)	(72,484)
Proceeds from issuance of shares, stock option plan	5,375	81
Lease principal payments	(3,716)	(2,904)
Dividends paid	(31,638)	(31,613)
Net cash used in financing	(97,987)	(606,920)
Increase (decrease) in cash and cash equivalents, during the year	(142,127)	357,510
Exchange rate changes on foreign currency cash balances	(1,922)	(6,607)
Cash and cash equivalents, beginning of year	1,062,431	711,528
Cash and cash equivalents, end of year	918,382	1,062,431
Cash and cash equivalents is comprised of:
Cash	503,496	427,986
Cash equivalents	$ 414,886	$ 634,445

Cameco Corporation

Cameco Corporation	12 Months Ended
	Dec. 31, 2020
Corporation [Abstract]
Cameco Corporation	1 . Cameco Corporation Cameco Corporation is incorporated under the Canada Business Corporations Act. The address of its registered office is 2121 11th Street West, Saskatoon, Saskatchewan, S7M 1J3. The consolidated financial statements as at and for the year ended December 31, 2020 comprise Cameco Corporation and its subsidiaries (collectively, the Company or Cameco) and the Company’s interests in ass ociates and joint arrangements. Cameco is one of the world’s largest providers of the uranium needed to generate clean, reliabl e baseload electricity around the globe. The Company has mines in northern Saskatchewan and the United States, as well as a 40% interest in Joint Venture Inkai LLP (JV Inkai ), a joint arrangement with Joint Stock Company National Atomic Company Kazatomprom ( Kazatomprom ) , located in Kazakhstan. JV Inkai is accounted for on an equity basis (see note 11 ). Cameco’s Cigar Lake mine was placed in a temporary state of care and maintenance in March of 2020 due to the global COVID-19 pandemic. While production r esumed in September, the mine returned to a temporary state of care and maintenance in January 2021 as a result of the pandemic . Cameco also has two other operations in northern Saskatchewan which are in care and maintenance. Rabbit Lake was placed in care and maintenance in the second quarter of 2016 while operations at McArthur River/Key Lake were suspended indefinitely in the third quarter of 2018. Cameco’s operations in the United States, Crow Butte and Smith Ranch-Highland, are also not currently producing as the decision was made in 2016 to curtail production and defer all wellfield development. See note 28 for the financial statement impact. The Company is also a leading provider of nuclear fuel processing services, supplying much of the world’s r eactor fleet with the fuel to generate one of the cleanest sources of electricity available today. It operates the world’s largest commercial refinery in Blind River, Ontario, controls about 24% of the world UF 6 primary conversion capacity in Port Hope, On tario and is a leading manufacturer of fuel assemblies and reactor components for CANDU reactors at facilities in Port Hope and Cobourg, Ontario . Also a result of the COVID-19 pandemic, production was temporarily suspended at the Port Hope UF 6 conversion p lant and at the Blind River refinery for approximately four weeks in the second quarter of 2020. See note 28 for the financial statement impact.

Significant accounting policies

Significant accounting policies	12 Months Ended
	Dec. 31, 2020
Significant Accounting Policies [Abstract]
Significant accounting policies	2 . Significant accounting policies A. Statement of compliance These consolidated financial statements have been prepared in accordance with International Financial Reporting Standards (IFRS) as issued by the International Accounting Standards Board (IASB). These consolidated financial statements were authorized for issuance by the Company’s board of directors on February 9 , 2021 . B. Basis of presentation These consolidated financial statements are presented in Canadian dollars, which is the Company’s functional currency. All financial information is presented in Canadian dollars , unless otherwise noted. A mounts presented in tabular format have been rounded to the nearest thousand except per share amounts and where otherwise noted. The consolidated financial statements have been prepared on the historical cost ba sis except for the following material items which are measured on an alternative basis at each reporting date: Derivative financial instruments Fair value through profit or loss (FVTPL) Equity investments Fair value through other comprehensive income (FVOCI) Liabilities for cash-settled share-based payment arrangements FVTPL Net defined benefit liability Fair value of plan assets less the present value of the defined benefit obligation The preparation of the consolidated financial statements in conformity with IFRS requires management to make judgments, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets, liabilities, revenue an d expenses. Actual results may vary from these estimates. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods aff ected. The areas involving a higher degree of judgment or complexity, or areas where assumptions and estimates are significant to the consolidated financial statements are disclosed in note 5 . This summary of significant accounting policies is a descri ption of the accounting methods and practices that have been used in the preparation of these consolidated financial statements and is presented to assist the reader in interpreting the statements contained herein. These accounting policies have been appli ed consistently to all entities within the consolidated group. C. Consolidation principles i. Business combinations The acquisition method of accounting is used to account for the acquisition of subsidiaries by the Company. The Company measures goodw ill at the acquisition date as the fair value of the consideration transferred, including the recognized amount of any non-controlling interests in the acquiree, less the net recognized amount (generally fair value) of the identifiable assets acquired and liabilities assumed, all measured as of the acquisition date. When the excess is negative, a bargain purchase gain is recognized immediately in earnings. In a business combination achieved in stages, the acquisition date fair value of the Company’s previou sly held equity interest in the acquiree is also considered in computing goodwill. Consideration transferred includes the fair values of the assets transferred, liabilities incurred and equity interests issued by the Company. Consideration also includes th e fair value of any contingent consideration and share-based compensation awards that are replaced mandatorily in a business combination. The Company elects on a transaction-by-transaction basis whether to measure any non-controlling interest at fair value , or at their proportionate share of the recognized amount of the identifiable net assets of the acquiree, at the acquisition date. Acquisition-related costs are expensed as incurred, except for those costs related to the issue of debt or equity instrument s. ii. Subsidiaries The consolidated financial statements include the accounts of Cameco and its subsidiaries. Subsidiaries are entities over which the Company has control. Subsidiaries are fully consolidated from the d ate on which control is acquired b y the Company and are deconsolidated from the date that control ceases. iii. Investments in equity-accounted investees Cameco’s investments in equity-accounted investees include investments in associates . Associates are those entities over which the Comp any has significant influence, but not control or joint control, over the financial and operating policies. Significant influence is presumed to exist when the Company holds between 20% and 50% of the voting power of another entity, but can also arise wher e the Company holds less than 20% if it has the power to be actively involved and influential in policy decisions affecting the entity. Investments in associates are accounted for using the equity method. The equity method involves the recording of the in itial investment at cost and the subsequent adjusting of the carrying value of the investment for Cameco’s proportionate share of the earnings or loss and any other changes in the associates’ net assets, such as dividends. The cost of the investment includ es transaction costs. Adjustments are made to align the accounting policies of the associate with those of the Company before applying the equity method. When the Company’s share of losses exceeds its interest in an equity-accounted investee, the carrying amount of that interest is reduced to zero, and the recognition of further losses is discontinued except to the extent that the Company has incurred legal or constructive obligations or made payments on behalf of the associate. If the associate subsequent ly reports profits, Cameco resumes recognizing its share of those profits only after its share of the profits equals the share of losses not recognized. iv. Joint arrangements A joint arrangement can take the form of a joint operation or joint venture. All joint arrangements involve a contractual arrangement that establishes joint control. A joint operation is a joint arrangement whereby the parties that have joint control of the arrangement have rights to the assets, and obligations for the liabilities , relating to the arrangement. A joint operation may or may not be structured through a separate vehicle. These arrangements involve joint control of one or more of the assets acquired or contributed for the purpose of the joint operation. The consolidated financial statements of the Company include its share of the assets in such joint operations, together with its share of the liabilities, revenues and expenses arising jointly or otherwise from those operations. All such amounts are measured in accordance with the terms of each arrangement. A joint venture is a joint arrangement whereby the parties that have joint control of the arrangement have rights to the net assets of the arrangement. A joint venture is always structured through a separate vehicle. It operates in the same way as other entities, controlling the assets of the joint venture, earning its own revenue and incurring its own liabilities and expenses. Interests in joint ventures are accounted for using the equity method of accounting, whereby t he Company’s proportionate interest in the assets, liabilities, revenues and expenses of jointly controlled entities are recognized on a single line in the consolidated statements of financial position and consolidated statements of earnings. The share of joint ventures results is recognized in the Company’s consolidated financial statements from the date that joint control commences until the date at which it ceases. v. Transactions eliminated on consolidation Intra-group balances and transactions, and any unrealized income and expenses arising from intra-group transactions, are eliminated in preparing the consolidated financial statements. Unrealized gains arising from transactions with equity-accounted investees are eliminated against the investment t o the extent of the Company’s interest in the investee. Unrealized losses are eliminated in the same manner as unrealized gains, but only to the extent that there is no evidence of impairment. D. Foreign currency translation Items included in the financial statements of each of Cameco’s subsidiaries, associates and joint arrangements are measured using their functional currency, which is the currency of the primary economic environment in which the entity operates. The consoli dated financial statements are presented in Canadian dollars, which is Cameco’s functional and presentation currency. i. Foreign currency transactions Foreign currency transactions are translated into the respective functional currency of the Company a nd its entities using the exchange rates prevailing at the dates of the transactions. At the reporting date, monetary assets and liabilities denominated in foreign currencies are translated to the functional currency at the exchange rate at that date. Non- monetary items that are measured in terms of historical cost in a foreign currency are translated using the exchange rate at the date of the transaction. The applicable exchange gains and losses arising on these transactions are reflected in earnings with the exception of foreign exchange gains or losses on provisions for decommissioning and reclamation activities that are in a foreign currency, which are capitalized in property, plant and equipment. ii. Foreign operations The assets and liabilities of f oreign operations, including goodwill and fair value adjustments arising on acquisition, are translated to Canadian dollars at exchange rates at the reporting dates. The revenues and expenses of foreign operations are translated to Canadian dollars at exch ange rates at the dates of the transactions. Foreign currency differences are recognized in other comprehensive income. When a foreign operation is disposed of, in whole , the relevant amount in the foreign currency translation account is transferred to ear nings as part of the gain or loss on disposal. When the settlement of a monetary item receivable from or payable to a foreign operation is neither planned nor likely in the foreseeable future, foreign exchange gains and losses arising from such a monetary item are considered to form part of the net investment in a foreign operation, and are recognized in other comprehensive income and presented within equity in the foreign currency translation account. E. Cash and cash equivalents Cash and cash equivalent s consists of balances with financial institutions and investments in money market instruments, which have a term to maturity of three months or less at the time of purchase and are measured at amortized cost . F. Short-term investment s Short-term investments are comprised of money market instruments with terms to maturity between three and 12 months and are measured at amortized cost. G. Inventories Inventories of broken ore, uranium concentrates, and refined and converted product s are measured at the lower of cost and net realizable value. Cost includes direct materials, direct labour, operational overhead expenses and depreciation. Net realizable value is the estimated selling price in the ordinary course of business, less the es timated costs of completion and selling expenses. Consumable supplies and spares are valued at the lower of cost or replacement value. H. Property, plant and equipment i. Buildings, plant and equipment and other Items of property, plant and equipment are measured at cost less accumulated depreciation and impairment charges. The cost of self-constructed assets includes the cost of materials and direct labour, borrowing costs and any other costs directly attributable to bringing the assets to the locati on and condition necessary for them to be capable of operating in the manner intended by management, including the initial estimate of the cost of dismantling and removing the items and restoring the site on which they are located. When components of an it em of property, plant and equipment have different useful lives, they are accounted for as separate items of property, plant and equipment and depreciated separately. Gains and losses on disposal of an item of property, plant and equipment are determined b y comparing the proceeds from disposal with the carrying amount of property, plant and equipment, and are recognized in earnings. ii. Mineral properties and mine development costs The decision to develop a mine property within a project area is based on an assessment of the commercial viability of the property, the availability of financing and the existence of markets for the product. Once the decision to proceed to development is made, development and other expenditures relating to the project area are deferred as part of assets under construction and disclosed as a component of property, plant and equipment with the intention that these will be depreciated by charges against earnings from future mining operations. No depreciation is charged against the property until the production stage commences. After a mine property has been brought into the production stage , costs of any additional work on that property are expensed as incurred, except for large development programs, which will be deferred and depr eciated over the remaining life of the related assets. The production stage is reached when a mine property is in the condition necessary for it to be capable of operating in the manner intended by management. The criteria used to assess the start date of the production stage are determined based on the nature of each mine construction project, including the complexity of a mine site. A range of factors is considered when determining whether the production stage has been reached, which includes, but is not limited to, the demonstration of sustainable production at or near the level intended (such as the demonstration of continuous throughput levels at or above a target percentage of the design capacity). iii. Depreciation Depreciation is calculated over the depreciable amount, which is the cost of the asset less its residual value. Assets which are unrelated to production are depreciated according to the straight-line method based on estimated useful lives as follows: Land Not depreciated Buildings 15 - 25 years Plant and equipment 3 - 15 years Furniture and fixtures 3 - 10 years Other 3 - 5 years Mining properties and certain mining and conversion assets for which the economic benefits from the asset are consumed in a pattern which is linked to the production level are depreciated according to the unit-of-production method. For conversion assets, the amount of depreciation is measured by the portion of the facilities' total estimated lifetime production that is produ ced in that period. For mining assets and properties, the amount of depreciation or depletion is measured by the portion of the mines' proven and probable mineral reserves recovered during the period. Depreciation methods, useful lives and residual values are reviewed at each reporting period and are adjusted if appropriate. iv. Borrowing costs Borrowing costs on funds directly attributable to finance the acquisition, production or construction of a qualifying asset are capitalized until such time as sub stantially all the activities necessary to prepare the qualifying asset for its intended use are complete. A qualifying asset is one that takes a substantial period of time to prepare for its intended use. Capitalization is discontinued when the asset ente rs the production stage or development ceases. Where the funds used to finance a project form part of general borrowings, interest is capitalized based on the weighted average interest rate applicable to the general borrowings outstanding during the period of construction. v. Repairs and maintenance The cost of replacing a component of property, plant and equipment is capitalized if it is probable that future economic benefits embodied within the component will flow to the Company. The carrying amount o f the replaced component is derecognized. Costs of routine maintenance and repair are charged to products and services sold. I. Goodwill and intangible assets Goodwill arising from the acquisition of subsidiaries is initially recognized at cost, measured as the excess of the fair value of the consideration paid over the fair value of the identifiable net assets acquired . At the date of acquisition, goodwill is allocated to the cash generating unit (CGU), or group of CGUs that is expected to receive the ec onomic benefits of the business combination . Goodwill is subsequently measured at cost, less accumulated impairment losses. Intangible assets acquired individually or as part of a group of assets are initially recognized at cost and measured subsequently a t cost less accumulated amortization and impairment losses. Subsequent expenditure is capitalized only when it increases the future economic benefits embodied in the specific asset to which it relates. The cost of a group of intangible assets acquired in a transaction, including those acquired in a business combination that meet the specified criteria for recognition apart from goodwill, is allocated to the individual assets acquired based on their relative fair values. Intangible assets that have finite us eful lives are amortized over their estimated remaining useful lives. Amortization methods and useful lives are reviewed at each reporting period and are adjusted if appropriate. J. Lease s Cameco recognizes a right-of-use asset and a lease liability at t he lease commencement date. The right-of-use asset is initially measured at cost, which is the initial amount of the lease liability adjusted for any lease payments made at or before the commencement date, plus any initial direct costs incurred, less any l ease incentives received, and subsequently at cost less any accumulated depreciation and impairment losses. The right-of-use asset is subsequently depreciated using the straight-line method from the commencement date to the end of the lease term, unless th e cost of the right-of-use asset reflect s that the Company will exer cise a purchase option, in which case the right-of-use asset will be deprec iated on the same basis as that of property, plant and equipment . The lease liability is measured at amortized co st using the effective interest method. It is initially measured at the present value of the lease payments that are not paid at the commencement date, discounted using the interest rate implicit in the lease, or, if that rate cannot be readily determined, the Company’s incremental borrowing rate. Generally, Cameco uses its incremental borrowing rate as the discount rate . Current borrowing rates available for classes of leased assets are compared with the rates of Cameco’s existing debt facilities to ensure that use of the Company’s incremental borrowing rate is reasonable. The lease liability is subsequently increased by the interest cost on the lease liability and decreased by lease payments made. It is remeasured when there is a change in future lease pay ments arising from a change in an index or rate, a change in the estimate of the amount expected to be payable under a residual value guarantee, or as appropriate, changes in the assessment of whether a purchase or extension option is reasonably certain to be exercised or a termination option is reasonably certain not to be exercised . Cameco uses judgement in determining the lease term for some lease contracts that include renewal options. The assessment of whether the Company is reasonably certain to exerc ise such options impacts the lease term, which affects the amount of lease liabilities and right-of-use assets recognized . The Company has elected not to recognize right-of-use assets and lease liabilities for leases of low-value assets and short-term leas es that have a lease term of 12 months or less. The lease payments associated with these leases are recognized as an expense on a straight-line basis over the lease term . K. Finance income and finance costs Finance income comprises interest income on f unds invested . Interest income and interest expense are recognized in earnings as they accrue , using the effective interest method. Finance costs comprise interest and fees on borrowings, unwinding of the discount on provisions and costs incurred on redemp tion of debentures . Borrowing costs that are not directly attributable to the acquisition, construction or production of a qualifying asset are expensed in the period incurred. L. Research and development costs Expenditures on research are charged agains t earnings when incurred. Development costs are recognized as assets when the Company can demonstrate technical feasibility and that the asset will generate probable future economic benefits. M. Impairment i . Non-derivative financial assets Cameco r ecognizes loss allowances for expected credit losses (ECLs) on financial assets measured at amortized cost, debt investments measured at FVOCI, and contract assets. It measures loss allowances at an amount equal to lifetime ECLs, except for debt securities that are determined to have low credit risk at the reporting date and other debt securities, loans advanced and bank balances for which credit risk has not increased significantly since initial recognition. For these, loss allowances are measured equal to 12-month ECLs. Lifetime ECLs are the ECLs that result from all possible default events over the expected life of a financial instrument while 12-month ECLs are the portion of ECLs that result from default events that are possible within the 12 months after the reporting date (or a shorter period if the expected life of the instrument is less than 12 months). The maximum period considered when estimating ECLs is the maximum contractual period over which the Company is exposed to credit risk. ECLs are a probability-weighted estimate of credit losses. Credit losses are m easured as the present value of the difference between the cash flows due to the entity in accordance with the contract and the cash flows that the Company expects to receive. ECLs are discounted at the effective interest rate of the financial asset. When determining whether the credit risk of a financial asset has increased significantly since initial recognition and when estimating ECLs, the Company considers reasonable and supportable information that is relevant and available without undue cost or effor t. This includes both quantitative and qualitative information and analysis, based on the Company’s historical experience and informed credit assessment and including forward-looking information. The Company considers a financial asset to be in default whe n the borrower is unlikely to pay its credit obligations in full, without recourse by Cameco to actions such as realizing security (if any is held). The Company considers a debt security to have low credit risk when it is at least an A (low) DBRS or A- S&P rating. Financial assets carried at amortized cost and debt securities at FVOCI are assessed at each reporting date to determine whether they are ‘credit-impaired’ . A financial asset is ‘credit-impaired’ when one or more events that have a detrimental eff ect on the estimated future cash flows of the financial asset have occurred. E vidence can include significant financial difficulty of the borrower or issuer , a breach of contract, restructuring of an amount due to the Company on terms that the Company woul d not consider otherwise, indications that a debtor or issuer will enter bankruptcy or other financial reorganization , or the disappearance of an active market for a security . Loss allowances for financial assets measured at amortized cost are deducted fro m the gross carrying amount of the assets. For debt securities at FVOCI, the loss allowance is charged to earnings and is recognized in OCI. The gross carrying amount of a financial asset is written off when the Company has no reasonable expectations of re covering a financial asset in its entirety or a portion thereof . ii. Non-financial assets The carrying amounts of Cameco’s non-financial assets are reviewed at each reporting date to determine whether there is any indication of impairment. If any such i ndication exists, then the asset’s recoverable amount is estimated. Goodwill is tested annually for impairment. For impairment testing, assets are grouped together into CGUs which are the smallest group of assets that generate cash inflows from continuing use that are largely independent of the cash inflows of other assets or CGUs. Goodwill arising from a business combination is allocated to CGUs or groups of CGUs that are expected to benefit from the synergies of the combination. The recoverable amount of an asset or CGU is the greater of its value in use and its fair value less costs to sell. Value in use is based on the estimated future cash flows, discounted to their present value using a pre-tax discount rate that reflects current market assessments of the time value of money and the risks specific to the asset or CGU. Fair value is determined as the amount that would be obtained from the sale of the asset or CGU in an arm’s-length transaction between knowledgeable and willing parties. For exploration p roperties, fair value is based on the implied fair value of the resources in place using comparable market transaction metrics. An impairment loss is recognized if the carrying amount of an asset or its CGU exceeds its recoverable amount. Impairment losses are recognized in earnings. Impairment losses recognized in respect of CGUs are allocated first to reduce the carrying amount of any goodwill allocated to the CGU, and then to reduce the carrying amounts of the other assets in the CGU on a pro rata basis. Impairment losses recognized in prior periods are assessed at each reporting date whenever events or changes in circumstances indicate that the impairment may have reversed. If the impairment has reversed, the carrying amount of the asset is increased to its recoverable amount. An impairment loss is reversed only to the extent that the asset’s carrying amount does not exceed the carrying amount that would have been determined, net of depreciation or amortization, if no impairment loss had been recognized. A reversal of an impairment loss is recognized immediately in earnings. An impairment loss in respect of goodwill is not reversed. N. Exploration and evaluation expenditures Exploration and evaluation expenditures are those expenditures incurred by the C ompany in connection with the exploration for and evaluation of mineral resources before the technical feasibility and commercial viability of extracting a mineral resource are demonstrable. These expenditures include researching and analyzing existing exp loration data, conducting geological studies, exploratory drilling and sampling, and compiling prefeasibility and feasibility studies. Exploration and evaluation expenditures are charged against earnings as incurred, except when there is a high degree of c onfidence in the viability of the project and it is probable that these costs will be recovered through future development and exploitation. The technical feasibility and commercial viability of extracting a resource is considered to be determinable based on several factors, including the existence of proven and probable reserves and the demonstration that future economic benefits are probable. When an area is determined to be technically feasible and commercially viable, the exploration and evaluation assets attributable to that area are first tested for impairment and then transferred to property, plant and equipment. Exploration and evaluation costs that have been acquired in a business combination or asset acquisition are capitalized u nder the scope of IFRS 6, Exploration for and Evaluation of Mineral Resources , and are reported as part of property, plant and equipment. O. Provisions A provision is recognized if, as a result of a past event, the Company has a present legal or construc tive obligation that can be estimated reliably, and it is probable that an outflow of economic benefits will be required to settle the obligation. Provisions are determined by discounting the risk-adjusted expected future cash flows at a pre-tax risk-free rate that reflects current market assessments of the time value of money. The unwinding of the discount is recognized as a finance cost . i . Environmental restoration The mining, extraction and processing activities of the Company normally give rise to obligations for site closure and environmental restoration. Closure and restoration can include facility decommissioning and dismantling, removal or treatment of waste materials, as well as site and land restoration. The Company provides for the closure, r eclamation and decommissioning of its operating sites in the financial period when the related environmental disturbance occurs, based on the estimated future costs using information available at the reporting date. Costs included in the provision comprise all closure and restoration activity expected to occur gradually over the life of the operation and at the time of closure. Routine operating costs that may impact the ultimate closure and restoration activities, such as waste material handling conducted as a normal part of a mining or production process, are not included in the provision. The timing of the actual closure and restoration expenditure is dependent upon a number of factors such as the life and nature of the asset, the operating licence condit ions and the environment in which the mine operates. Closure and restoration provisions are measured at the expected value of future cash flows, discounted to their present value using a current pre-tax risk-free rate. Significant judgments and estimates a re involved in deriving the expectations of future activities and the amount and timing of the associated cash flows. At the time a provision is initially recognized, to the extent that it is probable that future economic benefits associated with the recla mation, decommissioning and restoration expenditure will flow to the Company, the corresponding cost is capitalized as an asset. The capitalized cost of closure and restoration activities is recognized in property, plant and equipment and depreciated on a unit-of-production basis. The value of the provision is gradually increased over time as the effect of discounting unwinds. The unwinding of the discount is an expense recognized in finance costs. Closure and rehabilitation provisions are also adjusted for changes in estimates. The provision is reviewed at each reporting date for changes to obligations, legislation or discount rates that effect change in cost estimates or life of operations. The cost of the related asset is adjusted for changes in the provi sion resulting from changes in estimated cash flows or discount rates, and the adjusted cost of the asset is depreciated prospectively. ii. Waste disposal The refining, conversion and manufacturing processes generate certain uranium-contaminated waste. The Company has established strict procedures to ensure this waste is disposed of safely. A provision for waste disposal costs in respect of these materials is recognized when they are generated. Costs associated with the disposal, the timing of cash flows and discount rates are estimated both at initial recognition and subsequent measurement. P. Employee future benefits i . Pension obligations The Company accrues its obligations under employee benefit plans. The Company has both defined benefit and defined contribution plans. A defined contribution plan is a pension plan under which the Company pays fixed contributions into a separate entity. The Company has no legal or constructive obligations to pay further contributions if the fund does not hold s ufficient assets to pay all employees the benefits relating to employee service in the current and prior periods. A defined benefit plan is a pension plan other than a defined contribution plan. Typically, defined benefit plans define an amount of pension benefit that an employee will receive on retirement, usually dependent on one or more factors such as age, years of service and compensation. The liability recognized in the consolidated statements of financial position in respect of defined benefit pensio n plans is the present value of the defined benefit obligation at the reporting date less the fair value of plan assets. The defined benefit obligation is calculated annually, by qualified independent actuaries using the projected unit credit method prorat ed on service and management's best estimate of expecte

Accounting standards

Accounting standards	12 Months Ended
	Dec. 31, 2020
Accounting Standards [Abstract]
Accounting standards	3 . Accounting standards A. Changes in accounting policy A number of amendments to existing standards became effective January 1, 2020 but they d id not have a n effect on the Company’s financial statements . B. New standards and interpretations not yet adopted A number of amendments to existing standards are not yet effective for the year ended December 31, 2020 and have not been applied in preparing these consolidated financial statements. Cameco does not intend to early adopt an y of the amendments and does not expect them to have a material impact on its financial statements.

Determination of fair values

Determination of fair values	12 Months Ended
	Dec. 31, 2020
Fair Value Measurement [Abstract]
Determination of fair values	4 . Determination of fair values A number of the Company’s accounting policies and disclosures require the measurement of fair value, for both financial and non-financial assets and liabilities. The fair value of an asset or liability is generally estimated as the amount that would be received on sale of an asset, or paid to transfer a liability in an orderly transaction between market participants at the reporting date. Fair values of assets and liabilities traded in an active market are determined by reference to last quoted prices, in the principal market for the asset or liability. In the absence of an active market for an asset or liability, fair values are determined based on market quotes fo r assets or liabilities with similar characteristics and risk profiles, or through other valuation techniques. Fair values determined using valuation techniques require the use of inputs, which are obtained from external, readily observable market data whe n available. In some circumstances, inputs that are not based on observable data must be used. In these cases, the estimated fair values may be adjusted in order to account for valuation uncertainty, or to reflect the assumptions that market participants w ould use in pricing the asset or liability. All fair value measurements are categorized into one of three hierarchy levels, described below, for disclosure purposes. Each level is based on the transparency of the inputs used to measure the fair values of assets and liabilities: Level 1 – Values based on unadjusted quoted prices in active markets that are accessible at the reporting date for identical assets or liabilities. Level 2 – Values based on quoted prices in markets that are not active or model inpu ts that are observable either directly or indirectly for substantially the full term of the asset or liability. Level 3 – Values based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair valu e measurement. When the inputs used to measure fair value fall within more than one level of the hierarchy, the level within which the fair value measurement is categorized is based on the lowest level input that is significant to the fair value measuremen t in its entirety. Transfers between levels of the fair value hierarchy are recognized at the end of the reporting period during which the transfer occurred. There were no transfers between level 1, level 2, or level 3 during the period. Cameco does not ha ve any recurring fair value measurements that are categorized as level 3 as of the reporting date. Further information about the techniques and assumptions used to measure fair values is included in the following notes: Note 24 - Share-based compensation plans Note 26 - Financial instruments and risk management

Use of estimates and judgments

Use of estimates and judgments	12 Months Ended
	Dec. 31, 2020
Use Of Estimates And Judgments [Abstract]
Use of estimates and judgments	5 . Use of estimates and judgments The preparation of the consolidated financial statements in conformity with IFRS requires management to make judgments, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets, liabilities, revenues a nd expenses. Actual results may differ from these estimates. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future period a ffected. Information about critical judgments in applying the accounting policies that have the most significant effect on the amounts recognized in the consolidated financial statements is discussed below. Further details of the nature of these judgments , estimates and assumptions may be found in the relevant notes to the consolidated financial statements. A. Recoverability of long-lived and intangible assets Cameco assesses the carrying values of property, plant and equipment, and intangible assets whe n there is an indication of possible impairment. If it is determined that carrying values of assets or goodwill cannot be recovered , the unrecoverable amounts are charged against current earnings. Recoverability is dependent upon assumptions and judgments regarding market conditions, costs of production, sustaining capital requirements and mineral reserves. Other assumptions used in t he calculation of recoverable amounts are discount rates, future cash flows and profit margins. A material change in assumptions may significantly impact the potential impairment of these assets. B. Cash generating units In performing impairment assessme nts of long-lived assets, assets that cannot be assessed individually are grouped together into the smallest group of assets that generates cash inflows that are largely independent of the cash inflows from other assets or groups of assets. Management is r equired to exercise judgment in identifying these CGUs. C. Provisions for decommissioning and reclamation of assets Significant decommissioning and reclamation activities are often not undertaken until near the end of the useful lives of the productive a ssets. Regulatory requirements and alternatives with respect to these activities are subject to change over time. A significant change to either the estimated costs , timing of the cash flows or mineral reserves may result in a material change in the amount charged to earnings. D. I ncome taxes Cameco operates in a number of tax jurisdictions and is, therefore, required to estimate its income taxes in each of these tax jurisdictions in preparing its consolidated financial statements. In calculating income t axes, consideration is given to factors such as tax rates in the different jurisdictions, non-deductible expenses, changes in tax law and management’s expectations of future operating results. Cameco estimates deferred income taxes based on temporary diffe rences between the income and losses reported in its consolidated financial statements and its taxable income and losses as determined under the applicable tax laws. The tax effect of these temporary differences is recorded as deferred tax assets or liabil ities in the consolidated financial statements. The calculation of income taxes requires the use of judgment and estimates. The determination of the recoverability of deferred tax assets is de pendent on assumptions and judg ments regarding future market con ditions, production rates and intercompany sales , which can materially impact estimated future taxable income. If these judgments and estimates prove to be inaccurate, future earn ings may be materially impacted. E. Mineral reserves Depreciation on proper ty, plant and equipment is primarily calculated using the unit-of-production method. This method allocates the cost of an asset to each period based on current period production as a portion of total lifetime production or a portion of estimated mineral re serves. Estimates of life-of-mine and amounts of mineral reserves are updated annually and are subject to judgment and significant change over time. If actual mineral reserves prove to be significantly different than the estimates, there could be a materia l impact on the amounts of depreciation charged to earnings.

Accounts receivable

Accounts receivable	12 Months Ended
	Dec. 31, 2020
Trade And Other Receivables [Abstract]
Accounts receivable	6 . Accounts receivable 2020 2019 Trade receivables $ 166,054 $ 321,638 GST/VAT receivables 38,192 4,614 Other receivables 734 1,792 Total $ 204,980 $ 328,044 The Company’s exposure to credit and currency risks as well as credit losses related to trade and other receiva bles, excluding goods and services tax (G ST)/value added tax (VAT) rec eivables, is disclosed in note 26 .

Inventories

Inventories	12 Months Ended
	Dec. 31, 2020
Classes Of Inventories [Abstract]
Inventories	7 . Inventories 2020 2019 Uranium Concentrate $ 579,653 $ 204,123 Broken ore 45,387 51,094 625,040 255,217 Fuel services 52,273 62,701 Other 3,056 2,852 Total $ 680,369 $ 320,770 Cameco expensed $ 1,435 ,000,000 of inventory as cost of sales during 2020 ( 2019 - $ 1,398,000,000 ) .

Property, plant and equipment

Property, plant and equipment	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Property, plant and equipment	8 . Property, plant and equipment At December 31, 2020 Land Plant Furniture Exploration and and and Under and buildings equipment fixtures construction evaluation Total Cost Beginning of year $ 5,050,115 $ 2,678,165 $ 80,869 $ 132,457 $ 1,071,840 $ 9,013,446 Additions 2,030 7,097 855 67,477 3 77,462 Transfers 37,971 21,405 2,554 (60,391) - 1,539 Change in reclamation provision [note 15] 151,558 - - - - 151,558 Disposals (1,678) (3,385) (5,299) (492) (99) (10,953) Effect of movements in exchange rates (15,663) (3,438) (68) - 53,739 34,570 End of year 5,224,333 2,699,844 78,911 139,051 1,125,483 9,267,622 Accumulated depreciation and impairment Beginning of year 2,936,088 1,793,049 76,601 36,799 458,386 5,300,923 Depreciation charge 84,261 89,550 3,010 - - 176,821 Change in reclamation provision [note 15] (a) 23,921 - - - - 23,921 Disposals (903) (2,997) (5,299) (1) (150) (9,350) Effect of movements in exchange rates (12,075) (3,266) (66) - 25,427 10,020 End of year 3,031,292 1,876,336 74,246 36,798 483,663 5,502,335 Right-of-use assets Beginning of year 2,646 5,084 419 - - 8,149 Additions 75 22 2,124 - - 2,221 Disposals (40) (747) - - - (787) Depreciation charge (875) (498) (401) - - (1,774) Transfers - (1,539) - - - (1,539) End of year 1,806 2,322 2,142 - - 6,270 Net book value at December 31, 2020 $ 2,194,847 $ 825,830 $ 6,807 $ 102,253 $ 641,820 $ 3,771,557 At December 31, 2019 Land Plant Furniture Exploration and and and Under and buildings equipment fixtures construction evaluation Total Cost Beginning of year $ 5,039,313 $ 2,654,944 $ 80,083 $ 114,060 $ 1,121,061 $ 9,009,461 Additions 2,327 7,179 158 65,482 65 75,211 Transfers 17,157 28,453 951 (46,561) - - Change in reclamation provision 24,883 - - - - 24,883 Disposals (923) (3,486) (142) (507) (693) (5,751) Effect of movements in exchange rates (32,642) (8,925) (181) (17) (48,593) (90,358) End of year 5,050,115 2,678,165 80,869 132,457 1,071,840 9,013,446 Accumulated depreciation and impairment Beginning of year 2,835,037 1,697,178 74,860 36,799 483,661 5,127,535 Depreciation charge 128,579 105,700 2,057 - - 236,336 Change in reclamation provision (a) 2,732 - - - - 2,732 Disposals (225) (2,194) (139) - (639) (3,197) Effect of movements in exchange rates (30,035) (7,635) (177) - (24,636) (62,483) End of year 2,936,088 1,793,049 76,601 36,799 458,386 5,300,923 Right-of-use assets Beginning of year - - - - - - Additions 3,517 5,768 851 - - 10,136 Disposals - (9) - - - (9) Depreciation charge (871) (675) (432) - - (1,978) End of year 2,646 5,084 419 - - 8,149 Net book value at December 31, 2019 $ 2,116,673 $ 890,200 $ 4,687 $ 95,658 $ 613,454 $ 3,720,672 Cameco has contractual capital commitments of approximately $ 47 ,000,000 at December 31, 2020 . Certain of the contractual commitments may contain cancellation clauses, however the Company discloses the commitments based on management’s intent to fulfill the contract. The majority of this amount i s expected to be incurred in 2021 . (a) Asset retirement obligation assets are adjusted when the Company updates its reclamatio n provisions due to new cash flow estimates or changes in discount and inflation rates. When the assets of an operation have been written off due to an impairment, as is the case with our Rabbit Lake operation and some of our operations in the United States , the adjustment is recorded directly to the statement of earnings as other operating expense or income .

Intangible assets

Intangible assets	12 Months Ended
	Dec. 31, 2020
Intangible Assets And Goodwill [Abstract]
Goodwill and intangible assets	9 . I ntangible assets A. Reconciliation of carrying amount At December 31, 2020 Intellectual Contracts property Total Cost Beginning of year $ 113,707 $ 118,819 $ 232,526 Effect of movements in exchange rates (2,319) - (2,319) End of year 111,388 118,819 230,207 Accumulated amortization and impairment Beginning of year 111,094 61,022 172,116 Amortization charge 1,008 3,700 4,708 Effect of movements in exchange rates (2,439) - (2,439) End of year 109,663 64,722 174,385 Net book value at December 31, 2020 $ 1,725 $ 54,097 $ 55,822 At December 31, 2019 Intellectual Contracts property Total Cost Beginning of year $ 119,371 $ 118,819 $ 238,190 Effect of movements in exchange rates (5,664) - (5,664) End of year 113,707 118,819 232,526 Accumulated amortization and impairment Beginning of year 115,434 57,154 172,588 Amortization charge 1,181 3,868 5,049 Effect of movements in exchange rates (5,521) - (5,521) End of year 111,094 61,022 172,116 Net book value at December 31, 2019 $ 2,613 $ 57,797 $ 60,410 B. Amortization The intangible asset values relate to intellectual property acquired with Cameco Fuel Manufacturing Inc. (CFM) and purchase and sales contracts acquired with NUKEM. The CFM intellectual property is being amortized on a unit-of-production basis over its remaining life. Amortization is allocated to the cost of inventory and is recognized in cost of products and serv ices sold as inventory is sold. The purchase and sales contracts will be amortized to earnings over the remaining terms of the underlying contracts, which extend to 2022. Amortization of the purchase contracts is allocated to the cost of inventory an d is included in cost of products and services sold as inventory is sold. Sales contracts are amortized to revenue.

Long-term receivables, investme

Long-term receivables, investments and other	12 Months Ended
	Dec. 31, 2020
Categories Of Noncurrent Financial Assets [Abstract]
Long-term receivables, investments and other	10 . Long-term receivables, investments and other 2020 2019 Investments in equity securities [note 26] (a) $ 43,873 $ 24,408 Derivatives [note 26] 45,605 10,504 Investment tax credits 95,642 95,474 Amounts receivable related to tax dispute [note 21] (b) 303,222 303,222 Product loan (c) 176,904 176,904 Other 5,512 26,183 670,758 636,695 Less current portion (18,716) (6,564) Net $ 652,042 $ 630,131 (a) At January 1, 2018, Cameco designated the investments shown below as equity securities at FVOCI because these equity securities represent investments that the Company intends to hold for the long term for strategic purposes . There were no dividends recognized on any of these investments during the year. 2020 2019 Investment in Denison Mines Corp. $ 20,677 $ 13,292 Investment in UEX Corporation 13,005 7,253 Investment in ISO Energy Ltd. 6,923 1,481 Investment in GoviEx 2,875 2,000 Other 393 382 $ 43,873 $ 24,408 (b) Cameco was required to remit or otherwise secure 50% of the cash taxes and transfer pricing penalties, plus related interest and instalment penalties assessed, in relation to its dispute with Canada Revenue Agency (CRA) (see note 21 ). In light of our vi ew of the likely outcome of the case, Cameco expects to recover the amounts remitted to CRA, including cash taxes, interest and penalties totalling $303,222,000 already paid as at December 3 1 , 2020 (December 31, 2019 - $303,222,000) (note 21 ) . (c) During 2018, as a result of the decision to temporarily suspend production at the McArthur River mine, Cameco loaned 5,400 ,000 pounds of uranium concentrate to its joint venture partner, Orano Canada Inc., (Orano). Orano is obligated to repay us in kind with uranium concentrate no later than December 31, 2023 . The loan wa s recorded at Cameco’s weighted average cost of inventory .

Equity-accounted investee

Equity-accounted investee	12 Months Ended
	Dec. 31, 2020
Investments accounted for using equity method [Abstract]
Equity-accounted investee	11 . Equity-accounted investee JV Inkai is the operator of the Inkai uranium deposit located in Kazakhstan. Cameco holds a 40% interest and Kazatomprom holds a 60% interest in JV Inkai . Cameco does not have joint control over the joint venture and a s a result, Cameco accounts f or JV Inkai on an equity basis. JV Inkai is a uranium mining and milling operation that utilizes in-situ recovery (ISR) technology to extract uranium. The participants in JV Inkai purchase uranium from Inkai and, in turn, derive revenue directly from the sale of such product to third-party customers. The following tables summarize the financial information of JV Inkai (100%) : 2020 2019 Cash and cash equivalents $ 47,539 $ 16,699 Other current assets 115,647 139,324 Non-current assets 343,767 398,721 Current liabilities (26,397) (71,162) Non-current liabilities (39,991) (41,508) Net assets $ 440,565 $ 442,074 2020 2019 Revenue from products and services $ 252,764 $ 261,860 Cost of products and services sold (57,358) (64,199) Depreciation and amortization (24,081) (27,740) Finance income 367 651 Finance costs (825) (2,939) Other expense (12,305) (23,767) Income tax expense (44,804) (30,999) Net earnings 113,758 112,867 Other comprehensive loss (97) (1,773) Total comprehensive income $ 113,661 $ 111,094 The following table reconciles the summarized financial information to the carrying amount of Cameco’s interest in JV Inkai: 2020 2019 Opening net assets $ 442,074 $ 416,843 Total comprehensive income 113,661 111,094 Dividends declared (64,456) (66,369) Impact of foreign exchange (50,714) (19,494) Closing net assets 440,565 442,074 Cameco's share of net assets 176,226 176,830 Consolidating adjustments (a) (38,975) (30,633) Fair value increment (b) 89,184 91,697 Dividends declared but not received - 13,859 Dividends in excess of ownership percentage (c) (9,669) - Impact of foreign exchange 2,922 928 Carrying amount in the statement of financial position at December 31, 2020 $ 219,688 $ 252,681 (a) Cameco records certain consolidating adjustments to eliminate unrealized profit and amortize historical diffe rences in accounting policies. This amount is amortized to earnings over units of production. (b) Upon restructuring, Cameco assigned fair values to the assets and liabilities of JV Inkai. This increment is amortized to earnings over units of production . (c) Cameco’s share of dividends follows its production purchase entitlements which is currently hig her than its ownership interest .

Accounts payable and accrued li

Accounts payable and accrued liabilities	12 Months Ended
	Dec. 31, 2020
Trade And Other Current Payables [Abstract]
Accounts payable and accrued liabilities	12 . Accounts payable and accrued liabilities 2020 2019 Trade payables $ 137,190 $ 100,407 Non-trade payables 58,105 66,815 Payables due to related parties [note 24] 38,354 14,577 Total $ 233,649 $ 181,799 The Company’s exposure to currency and liquidity risk related to trade and other payables is disclosed in note 26 .

Long-term debt

Long-term debt	12 Months Ended
	Dec. 31, 2020
Noncurrent Liabilities [Abstract]
Long-term debt	13 . Long-term debt 2020 2019 Unsecured debentures Series E - 3.75% debentures due November 14, 2022 - 399,152 Series F - 5.09% debentures due November 14, 2042 99,319 99,302 Series G - 4.19% debentures due June 24, 2024 498,630 498,264 Series H - 2.95% debentures due October 21, 2027 397,592 - Total $ 995,541 $ 996,718 On October 21, 2020, Cameco issued $ 400,000,000 of Series H debentures which bear interest at a rate of 2.95 % per annum. The net proceeds of the issue after deducting expenses were approximately $ 397,500,000 . The debentures mature on October 21, 2027 and are being amortized at an effective interest rat e of 3.05 %. In conjunction with the issuance of the Series H debentures, on November 20, 2020, the $ 400,000,000 principal amount of the Series E debentures was redeemed. Cameco recognized $ 24,439,000 of finance costs in relation to the early redemption of these debentures (note 19 ). C ameco has a $ 1,00 0,000,000 unsecured revolving credit facility that is available until November 1, 2023 . Upon mutual agreement, the facility can be extended for an additional year on the anniversary date. In addition to direct borrowings under the facility, up to $ 100,000,000 can be used for the issuance of letters of credit and, to the extent necessary, it may be used to provide liquidity support for the Company’s commercial paper program. The agreement also provides the ability to increase the revolving credit facility above $ 1,00 0,000,000 by increments no less than $ 50,000,000 , to a total of $ 1,2 50,000,000 . The facility ranks equally with all of Cameco’s other senior debt. As of December 31, 2020 and 2019 , there were no amounts outstanding under this facility. Cameco has $ 1,698,340 ,000 ( 2019 - $ 1,719,120 ,000 ) in letter of credit facilities. Outstanding and committed letters of credit at December 31, 2020 amou nted to $ 1,596,488,000 ( 2019 - $ 1,528,603 ,000 ), the majority of which relate to future decommissioning and reclamation liabilities (note 15 ). Cameco is bound by a covenant in its revolving credit facility. The covenant requires a funded debt to tangible net worth ratio equal to or less than 1 :1. Non-co mpliance with this covenant could result in accelerated payment and termination of the revolving credi t facility. At December 31, 2020 , Cameco was in compliance with the covenant and does not expect its operating and investing activities in 2021 to b e constrained by it . The table below represents currently scheduled maturities of long-term debt: 2021 2022 2023 2024 2025 Thereafter Total $ - - - 498,630 - 496,911 $ 995,541

Other liabilities

Other liabilities	12 Months Ended
	Dec. 31, 2020
Other Liabilities [Abstract]
Other liabilities	14 . Other liabilities 2020 2019 Deferred sales [note 17] $ 14,382 $ 17,418 Derivatives [note 26] 4,733 12,524 Accrued pension and post-retirement benefit liability [note 25] 91,729 80,737 Lease obligation 7,951 12,869 Product loan (a) 6,045 - Other 67,838 63,452 192,678 187,000 Less: current portion (26,119) (33,073) Net $ 166,559 $ 153,927 Expenses related to short-term leases and leases of low-value assets were insignificant during 2020 . (a) The Company has standby product loan facilities with various counterparties. The arrangements allow it to borrow up to 2.0 million kgU of UF 6 conversion services and 2.6 million pounds of U 3 O 8 over the period 2020 to 2023 with repayment in kind up to D ecember 31, 2023 . Under the facilities, standby fees of up to 1 % are payable based on the market value of the facilities and interest is payable on the market value of any amounts drawn at rates ranging from 0.5 % to 2.0 %. During the year, Cameco borrowed 1 ,213,800 pounds of U 3 O 8 and 464,600 kgU of UF 6 conversion services. The U 3 O 8 loan was repaid during the year while repayment on the UF 6 loan is due no later than December 31, 2022. The loan is recorded at Cameco’s weighted average cost of inventory.

Provisions

Provisions	12 Months Ended
	Dec. 31, 2020
Provisions [Abstract]
Provisions	15 . Provisions Reclamation Waste disposal Total Beginning of year $ 1,050,675 $ 9,803 $ 1,060,478 Changes in estimates and discount rates [note 8] Capitalized in property, plant and equipment 127,637 - 127,637 Recognized in earnings [note 8] 23,921 (150) 23,771 Provisions used during the period (17,272) (368) (17,640) Unwinding of discount [note 19] 14,366 37 14,403 Effect of movements in exchange rates (9,727) - (9,727) End of period $ 1,189,600 $ 9,322 $ 1,198,922 Current $ 40,760 $ 1,775 $ 42,535 Non-current 1,148,840 7,547 1,156,387 $ 1,189,600 $ 9,322 $ 1,198,922 A. Reclamation provision Cameco's estimates of future decommissioning obligations are based on reclamation standards that satisfy regulatory requirements. Elements of uncertainty in estimating these amounts include potential changes in regulatory requirements, decommissioning and reclamation alternatives and amounts to be recovered from other parties. Cameco estimates total undiscounted future decommissioning and reclamation costs for its existing operating assets to be $ 1,130,495,000 ( 2019 - $ 1,127,487 ,000 ). The expected timing of these outflows is based on life-of-mine plans with the majority of expenditu res expected to occur after 2026 . These estimates are reviewed by Cameco technical personnel as required by regulatory agencies or more frequently as circumstances warrant. In connection with future decommissioning and reclamation costs, Cameco has provided financial assurances of $ 1,021,142,000 ( 2019 - $ 994,129 ,000 ) in the form of letters of credit to satisfy current regulatory requirements. The reclamation provision relates to the following segments: 2020 2019 Uranium $ 937,992 $ 831,352 Fuel services 251,608 219,323 Total $ 1,189,600 $ 1,050,675 B. Waste disposal The fuel services segment consists of the Blind River refinery, Port Hope conversion facility and Cameco Fuel Manufacturing Inc. . The refining, conversion and manufacturing processes generate certain uranium contaminated waste. These include contaminated combustible material (paper, rags, gloves, etc.) and contaminated non-combustible material (metal parts, soil from excavations, building and roofing materials, spent uranium concentrate drums, etc.). These materials can in some i nstances be recycled or reprocessed. A provision for waste disposal costs in respect of these materials is recognized when they are generated. Cameco estimates total undiscounted future costs related to existing waste disposal to be $ 8,044 ,000 ( 2019 - $ 8,451,000 ). The majority of these expenditures are expecte d to occur within the next five years.

Share capital

Share capital	12 Months Ended
	Dec. 31, 2020
Disclosure Of Classes Of Share Capital [Abstract]
Share capital	16 . Share capital Authorized share capital:  Unlimited number of first preferred shares  Unlimited number of second preferred shares  Unlimited number of voting common shares, no stated par value, not convertible or redeemable, and  One Class B share A. Common Shares Number issued (number of shares) 2020 2019 Beginning of year 395,797,732 395,792,732 Issued: Stock option plan [note 24] 465,009 5,000 End of year 396,262,741 395,797,732 All issued shares are fully paid. H olders of the common shares are entitled to exercise one vote per share at meetings of shareholders, are entitled to receive dividends if, as and when declared by our Board of Directors and are entitled to participate in any distribution of remaining assets following a liqui dation. The shares of Cameco are widely held and no shareholder, resident in Canada, is allowed to own more than 25 % of the Company’s outstanding common shares, either individually or together with as sociates. A non-resident of Canada is not allowed to own more than 15 %. In addition, no more than 25 % of total shareholder votes cast may be cast by non-resident shareholders. B. Class B share One Class B share issued during 1988 and assigned $ 1 of share capital entitles the shareholder to vote separately as a class in respect of any proposal to locate the head office of Cameco to a place not in the province of Saskatchewan . C. Dividends Dividends on Cameco Corporation common shares are declared in Canadian dollars. For the year ended December 31, 2020 , the dividend declared per sh are was $ 0.08 (December 31, 2019 - $ 0. 08 ).

Revenue

Revenue	12 Months Ended
	Dec. 31, 2020
Revenue [abstract]
Disclosure Of Revenue Explanatory	17 . Revenue Cameco’s sales contracts with customers contain both fixed and market-related pricing. Fixed-price contracts are typically based on a term-price indicator at the time the contract is accepted and escalated over the term of the contract. Market-related contracts are based on either the spot price or long-term price, and the price is quoted at the time of delivery rather than at the time the contract is accepted. These contracts often include a floor and/or ceiling prices, which are usually escalated over the term of the contract. Escalation is generally based o n a consumer price index. The Company’s contracts contain either one of these pricing mechanisms or a combination of the two. There is no variable consideration in the contracts and t herefore no revenue is considered constrained at the time of delivery . Cameco expenses the incremental costs of obtaining a contract as incurred as the amortization period is less than a year. The following table summarizes Cameco’s sales disaggregated by geographical region and contract type and includes a reconciliation to the Company ’s r eportable segments (note 28 ): For the year ended December 31, 2020 Uranium Fuel services Other Total Customer geographical region Americas $ 588,827 $ 206,011 $ 7,676 $ 802,514 Europe 323,565 123,864 3,331 450,760 Asia 499,378 47,421 - 546,799 $ 1,411,770 $ 377,296 $ 11,007 $ 1,800,073 Contract type Fixed-price $ 406,021 $ 355,552 $ 7,686 $ 769,259 Market-related 1,005,749 21,744 3,321 1,030,814 $ 1,411,770 $ 377,296 $ 11,007 $ 1,800,073 For the year ended December 31, 2019 Uranium Fuel services Other Total Customer geographical region Americas $ 569,535 $ 206,226 $ 59,300 $ 835,061 Europe 288,134 79,629 3,587 371,350 Asia 556,140 84,422 15,952 656,514 $ 1,413,809 $ 370,277 $ 78,839 $ 1,862,925 Contract type Fixed-price $ 349,021 $ 305,383 $ 69,703 $ 724,107 Market-related 1,064,788 64,894 9,136 1,138,818 $ 1,413,809 $ 370,277 $ 78,839 $ 1,862,925 Deferred sales The following table provides information about contract liabilities (note 14 ) from contracts with customers: 2020 2019 Beginning of year $ 17,418 $ 30,727 Additions 6,994 9,783 Recognized in revenue (10,026) (23,067) Effect of movements in exchange rates (4) (25) End of year $ 14,382 $ 17,418 Deferred sales primarily relates to advance consideration received from customers for future conversion deliveries and fuel fabrication services as well as revenue related to the storage of uranium and converted uranium held at Cameco facilities. The revenue related to the fuel fabricati on services and storage is recognized over time while the revenue related to future conversion deliveries is expected to be recognized between 20 21 and 20 27. Cameco recognized a reduction of revenue of $ 268,000 ( 2019 - revenue of $ 78,000 ) during 2020 from performance obligations satisfied (or partially satisfied) in previous periods. This is due to the difference between actual pricing indices and the estimates at the time of invoicing. Future sales commitments Cam eco’s sales portfolio consists of sho rt and long-term sales commitments. The contracts can be executed well in advance of a delivery and include both fixed and market-related pricing. The following table summarizes the expected future revenue, by segment, related to only fixed-price contracts with remaining future deliveries as follows: 2021 2022 2023 2024 2025 Thereafter Total Uranium $ 243,069 $ 189,351 $ 179,212 $ 166,581 $ 129,450 $ 416,947 $ 1,324,610 Fuel services 319,851 272,920 212,655 215,729 216,250 677,611 1,915,016 Other 4,212 - - - - - 4,212 Total $ 567,132 $ 462,271 $ 391,867 $ 382,310 $ 345,700 $ 1,094,558 $ 3,243,838 The sales contracts are denominated largely in US dollars and converted from US to Canadian dollars at a rate of $ 1.30 . The amounts in the table represent the consideration the Company will be entitled to receive when it satisfies the remaining performance obligations in the contracts. The amounts include assumptions about volumes for contracts that have volume flexibility. Cameco’s total revenue that will be earned will also include revenue from contracts with market-related pricing. The Company has elected to exclude these amounts from the table as the transaction price will not be known until the time of delivery. Contracts with an original duration of one year or less have been included in the table.

Employee benefit expense

Employee benefit expense	12 Months Ended
	Dec. 31, 2020
Classes Of Employee Benefits Expense [Abstract]
Employee benefit expense	18 . Employee benefit expense The following employee benefit expenses are included in cost of products and services sold, administration, exploration, research and development and property, plant and equipment: 2020 2019 Wages and salaries $ 226,725 $ 238,000 Statutory and company benefits 41,299 41,972 Expenses related to defined benefit plans [note 25] 5,256 4,790 Expenses related to defined contribution plans [note 25] 12,410 11,767 Equity-settled share-based compensation [note 24] 9,738 17,469 Cash-settled share-based compensation [note 24] 27,241 (1,437) Total $ 322,669 $ 312,561

Finance costs

Finance costs	12 Months Ended
	Dec. 31, 2020
Finance Costs [Abstract]
Finance costs	19 . Finance costs 2020 2019 Interest on long-term debt $ 43,340 $ 63,136 Unwinding of discount on provisions [note 15] 14,403 20,789 Redemption of Series E debentures [note 13] 24,439 - Other charges 13,951 14,697 Total $ 96,133 $ 98,622 No borrowing costs were determined to be eligible for capitalization during the year .

Other income (expense)

Other income (expense)	12 Months Ended
	Dec. 31, 2020
Other Income Expense [Abstract]
Other income (expense)	20 . Other income (expense) 2020 2019 Arbitration award (a) $ - $ 52,801 Foreign exchange gains (losses) 13,891 (18,961) Government assistance (b) 37,347 - Other 202 - Total $ 51,440 $ 33,840 (a) In the third quarter of 2019 , Cameco received an award from the tribunal of international arbitrators (Tribunal) with respect to its contract dispute with Tokyo Electric Power Company Holdings, Inc. (TEPCO). The Tribunal rejected TEPCO’s assertion that it had the right to terminate i ts uranium supply agreement and awarded damages of $ 40,300,000 (US). Damages were based on the Tribunal’s interpretation of losses under this supply agreement . (b) In response to the negative economic impact of COVID-19, the Government of Canada announced the Canada Emergency Wage Subsidy program (CEWS) . CEWS provides a subsidy on eligible remuneration based on certain criteria. During the year, the Company qualified for the subsidy for the periods April through December. There are no unfulfilled conditio ns and other contingencies attached to this government assistance. Cameco intends to apply for the CEWS in subsequent application periods, subject to continuing to meet the applicable qualification criteria.

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2020
Income Tax [Absract]
Income taxes	21 . Income taxes A. Significant components of deferred tax assets and liabilities Recognized in earnings As at December 31 2020 2019 2020 2019 Assets Property, plant and equipment $ (38,389) $ 74,039 $ 280,798 $ 319,185 Provision for reclamation 28,628 2,325 222,142 193,514 Inventories 4,071 (2,163) 4,071 - Foreign exploration and development 2 (14) 5,269 5,267 Income tax losses (gains) (7,629) (108,839) 382,712 390,341 Defined benefit plan actuarial losses - - 9,410 7,947 Long-term investments and other (5,678) (17,377) 32,276 40,423 Deferred tax assets (18,995) (52,029) 936,678 956,677 Liabilities Inventories (301) 301 - 301 Deferred tax liabilities (301) 301 - 301 Net deferred tax asset (liability) $ (18,694) $ (52,330) $ 936,678 $ 956,376 Deferred tax allocated as 2020 2019 Deferred tax assets $ 936,678 $ 956,376 Deferred tax liabilities - - Net deferred tax asset $ 936,678 $ 956,376 Cameco has recorded a deferred tax asset of $936,678,000 ( 2019 - $956,376,000). The realization of this deferred tax asset is dependent upon the generation of future taxable income in certain jurisdictions during the periods in which the Company’s deferred t ax assets are available. The Company considers whether it is probable that all or a portion of the deferred tax assets w ill not be realized. In making this assessment, management considers all available evidence, including recent financial operations, projected future taxable income and tax planning strategies. Based on projections of future taxable income over the periods in which the deferred tax assets are available, realization of these deferred tax assets is probable and consequently the deferred tax assets have been recorded . B. Movement in net deferred tax assets and liabilities 2020 2019 Deferred tax asset at beginning of year $ 956,376 $ 1,006,012 Expense for the year in net earnings (18,694) (52,330) Recovery (expense) for the year in other comprehensive income (1,006) 2,754 Effect of movements in exchange rates 2 (60) End of year $ 936,678 $ 956,376 C. Significant components of unrecognized deferred tax assets 2020 2019 Income tax losses $ 271,163 $ 280,330 Property, plant and equipment 2,204 2,321 Provision for reclamation 75,219 75,082 Long-term investments and other 60,223 70,380 Total $ 408,809 $ 428,113 D. Tax rate reconciliation T he provision for income taxes differs from the amount computed by applying the combined expected federal and provincial income tax rate to earnings before income taxes. The reasons for these differences are as follows: 2020 2019 Earnings (loss) before income taxes and non-controlling interest $ (39,531) $ 135,018 Combined federal and provincial tax rate 26.9% 26.9% Computed income tax expense (recovery) (10,634) 36,320 Increase (decrease) in taxes resulting from: Difference between Canadian rates and rates applicable to subsidiaries in other countries 42,028 5,558 Change in unrecognized deferred tax assets (7,766) 19,646 Share-based compensation plans 398 1,146 Change in legislation (1,978) - Income in equity-accounted investee (12,155) (12,074) Change in uncertain tax positions 2,455 2,572 Other permanent differences 1,318 7,909 Income tax expense $ 13,666 $ 61,077 E. Earnings and income taxes by jurisdiction 2020 2019 Earnings (loss) before income taxes Canada $ 72,809 $ 229,429 Foreign (112,340) (94,411) $ (39,531) $ 135,018 Current income taxes (recovery) Canada $ (394) $ 7,969 Foreign (4,634) 778 $ (5,028) $ 8,747 Deferred income taxes (recovery) Canada $ 9,122 $ 60,010 Foreign 9,572 (7,680) $ 18,694 $ 52,330 Income tax expense $ 13,666 $ 61,077 F. Reassessments Canada In 2008, as part of the ongoing annual audits of Cameco's Canadian tax returns, Canada Revenue Agency (CRA) disputed the transfer pricing structure and methodology used by Cameco and its wholly owned Swiss subsidiary, Cameco Europe Ltd., in respect of sale and purchase agreements for uranium products. From December 2008 to date, CRA issued notices of reassessment for the taxation years 2003 through 2014 , which in aggregate have increased Cameco's income for Canadian tax purposes by approximately $ 6 ,6 00,000,000 . CRA has also issued notices of reassessment for transfer pricing penalties for the years 2007 through 2011 in the amount of $ 371,000,000 . On June 26, 2020, the Federal Court of Appeal (Court of Appeal) released it s decision in the Company’s dispute with CRA . The Court of Appeal decision upholds the September 26 , 2018 decision of the Tax Court of Canada (Tax Court) which ruled in Cameco’s favour for the 2003, 2005 and 2006 tax years . The Court of Appeal decision upheld the Tax Court rul ing that our marketing and trading structure involving foreign subsidiaries and the related transfer pricing methodology used for certain intercompany uranium purchase and sale agreements were in full compl iance with Canadian laws for the three tax years in question. Management believes the principles in the decision apply to all subsequent tax years . On October 30, 2020, Cameco received notice that CRA made an application to the Supreme Court of Canada (Supreme Court) to seek leave to appeal the decision of the Court of Appeal. The Supreme Court will decide whether to hear the appeal or decline CRA’s request for leave. If the appeal proceeds, Cameco estimates that it could take until the second half of 2022 before a decision is rendere d by the Supreme Court . Despite the fact that Cameco believe s there is no basis to do so, and it is not the Company’s view of the likely outcome , CRA may continue to reassess Cameco using the methodology it reassess ed the 2003 through 2014 tax years . In that scenario, and including the $ 6 ,6 00,000,000 already reassessed, the Company could receive notices of reassessment for a total of approximately $ 8,700,000,000 for the years 2003 through 2020 , which would increase Cameco’s related tax expense by approximately $ 2,600,000,000 . In addition to penalties already imposed, CRA may continue to a pply penalties to taxation years subsequent to 2011. In that case, Cameco estimates that cash taxes and transfer pricing penalties would be between $ 1,950,000,000 and $ 2,150,000,000 . In addition, CRA may seek to apply interest and instalment penalties that would be material to Cameco. While in dispute, Cameco would be required to remit or otherwise secure 50 % of the cash taxes and transfer pricing penalties (between $ 970,000,000 and $ 1,070,000,000 ), plus related interest and instalment penalties assessed, w hich would be material to the Company. Cameco expects further actions regarding the tax years 2007 through 2014 will be suspended until the three years covered in the decision are finally resolved. CRA has recently proposed an alternative reassessing position for the 2014 tax year but has not reassessed on this basis. Management believes that the ultimate resolution will not be material to Cameco's financial position, results of operations or liquidity in the year(s) of resolution. However, r esolution of this matter as stipulated by CRA would be material to Cameco’s financial position, results of operations or liquidity in the year(s) of resolution and other unfavourable outcomes for the years 2003 to date could be material to Cameco's financial position, results of operations and cash flows in the year(s) of resolutio n. If CRA continues to pursue reassessments for tax years su bsequent to 2006, Cameco will continue to utilize its appeal rights under Canadian federal and provincial tax rule s . G. Income tax losses At December 31, 2020 , income tax losses carried forward of $2 ,399 ,647 ,000 ( 2019 - $ 2,509,669,000 ) are available to reduce taxable income. These losses expire as follows: Date of expiry Canada US Other Total 2026 $ - $ - $ 13,819 $ 13,819 2027 - - 2,841 2,841 2030 47 - - 47 2031 - 20,436 - 20,436 2032 272 22,010 - 22,282 2033 7,037 37,520 - 44,557 2034 365,039 20,697 4,850 390,586 2035 372,376 14,401 7,752 394,529 2036 211,299 43,769 6,106 261,174 2037 143 32,785 298 33,226 2038 5,581 35,357 - 40,938 2039 6,424 27,348 - 33,772 2040 3,669 21,798 - 25,467 No expiry - - 1,115,973 1,115,973 $ 971,887 $ 276,121 $ 1,151,639 $ 2,399,647 Included in the t able above is $ 1 ,013 ,730 ,000 ( 2019 - $ 1,048,264 ,000 ) of temporary differences related to loss carry forwards whe re no future benefit has been recognized .

Per share amounts

Per share amounts	12 Months Ended
	Dec. 31, 2020
Per Share Amounts [Abstract]
Per share amounts	22 . Per share amounts Per share amounts have been calculated based on the weighted average number of common shares outstanding during the period. The weighted average number of paid shares outstanding in 2020 was 395,829,380 ( 2019 - 395, 796,677 ). 2020 2019 Basic earnings (loss) per share computation Net earnings (loss) attributable to equity holders $ (53,169) $ 74,000 Weighted average common shares outstanding 395,829 395,797 Basic earnings (loss) per common share $ (0.13) $ 0.19 Diluted earnings (loss) per share computation Net earnings (loss) attributable to equity holders $ (53,169) $ 74,000 Weighted average common shares outstanding 395,829 395,797 Dilutive effect of stock options 214 258 Weighted average common shares outstanding, assuming dilution 396,043 396,055 Diluted earnings (loss) per common share $ (0.13) $ 0.19

Supplemental cash flow informat

Supplemental cash flow information	12 Months Ended
	Dec. 31, 2020
Statement Of Cash Flows Disclosure [Abstract]
Statements of cash flows	23 . Supplemental cash flow information Other operating items included in the statements of cash flows are as follows: 2020 2019 Changes in non-cash working capital: Accounts receivable $ 143,717 $ 58,488 Inventories (376,908) 113,388 Supplies and prepaid expenses (3,999) 3,612 Accounts payable and accrued liabilities 36,514 (53,477) Reclamation payments (17,640) (32,390) Other 25,399 6,857 Total $ (192,917) $ 96,478 The changes arising from financing activities were as follows: Long-term Interest Lease Dividends Share debt payable obligation payable capital Total Balance at January 1, 2020 $ 996,718 $ 3,030 $ 12,869 $ - $ 1,862,749 $ 2,875,366 Changes from financing cash flows: Dividends paid - - - (31,638) - (31,638) Interest paid - (65,280) (267) - - (65,547) Lease principal payments - - (3,716) - - (3,716) Shares issued, stock option plan - - - - 5,375 5,375 Repayment of long-term debt (400,000) - - - - (400,000) Proceeds of long-term debt 397,539 - - - - 397,539 Total cash changes (2,461) (65,280) (3,983) (31,638) 5,375 (97,987) Non-cash changes: Amortization of issue costs 1,284 - - - - 1,284 Dividends declared - - - 31,638 - 31,638 Interest expense - 66,228 267 - - 66,495 Right-of-use asset additions - - 2,221 - - 2,221 Right-of-use asset cancellations - - (2,165) - - (2,165) Joint operation lease obligations - - (1,361) - - (1,361) Shares issued, stock option plan - - - - 1,586 1,586 Foreign exchange - - 103 - - 103 Total non-cash changes 1,284 66,228 (935) 31,638 1,586 99,801 Balance at December 31, 2020 $ 995,541 $ 3,978 $ 7,951 $ - $ 1,869,710 $ 2,877,180

Share-based compensation plans

Share-based compensation plans	12 Months Ended
	Dec. 31, 2020
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Abstract]
Share-based compensation plans	24 . Share-based compensation plans The Company has the following plans: A. Stock option plan T he Company has established a stock option plan under which options to purchase common shares may be granted to employees of Cameco. Options granted under the stock option plan have an exercise price of not less than the closing price quoted on the Toronto Stock Exchange (TSX) for the common shares of Cameco on the trading day prior to the date on which the option is granted. The options carry vesting periods of one to three years, and expire eight years from the date granted . The aggregate number of common shares that may be issued pursuant to the Cameco stock option plan shall not exceed 43,017,198 of which 28,340,298 shares have been issued. Stock option transactions for the respective years were as follows: (Number of options) 2020 2019 Beginning of year 8,617,097 8,820,805 Options granted - 886,740 Options forfeited (81,991) (270,025) Options expired (1,911,558) (815,423) Options exercised [note 16] (465,009) (5,000) End of year 6,158,539 8,617,097 Exercisable 5,076,226 6,290,380 Weighted average exercise prices were as follows: 2020 2019 Beginning of year $17.44 $19.75 Options granted - 15.27 Options forfeited 22.22 22.59 Options expired 20.14 38.43 Options exercised 11.56 16.38 End of year $16.98 $17.44 Exercisable $17.73 $18.90 Total options outstanding and exercisable at December 31, 2020 were as follows: Options outstanding Options exercisable Option price per share Number Weighted average remaining life Weighted average exercisable price Number Weighted average exercisable price $11.32 - 15.83 3,060,721 5.0 $13.72 1,978,408 $13.85 $15.84 - 26.81 3,097,818 1.8 $20.21 3,097,818 $20.21 6,158,539 5,076,226 The foregoing options have expiry dates ranging from February 28, 2021 to February 28, 2027. B. Executive performance share unit (PSU) The Company has established a PSU plan whereby it provides each plan participant an annual grant of PSUs in an amount determined by the board. Each PSU represents one phantom common share that entitles the participant to a payment of one Cameco common share purchased on the open market, or cash with an equivalent market value, at the participant’s discretion provided they have met their ownership requirements , at the end of each three-year period if certain performance and vesting criteria have been met. The final value of the PSUs will be based on the value of Cameco common shares at the end of the three-year period and the number of PSUs that ultimately vest. During the vesting period, dividend equivalents accrue to the participants in the form of additional share units as of each normal cash dividend payment date of Cameco’s common shares. Vesting of PSUs at the end of the three-year period is based on Cameco’s ability to meet its annual operating targets a nd whether the participating executive remains employed by Cameco at the end of the three-year vesting period . Prior to 2020, total shareholder return over three years was also a vesting condition. If the participant elects a cash payout, the redemption am ount will be based on the volume-weighted average trading price of Cameco’s common shares on March 1 or, if March 1 is not a trading day, on the first trading day following March 1. As of December 31, 2020 , the total number of PSUs held by the participa nts, after adjusting for forfeitures on retirement, was 1,720,636 ( 2019 - 1, 465 , 618 ). C . Restricted share unit (RSU) The Company has established an RSU plan whereby it provides each plan participant an annual grant of RSUs in an amount determined by t he board. Each RSU represents one phantom common share that entitles the participant to a payment of one Cameco common share purchased on the open market, or cash with an equivalent market value, at the board’s discretion. The RSUs carry vesting periods of one to three years , and the final value of the units will be based on the value of Cameco common shares at the end of the vesting periods. In addition, certain eligible participants have a single vesting date on the third anniversary of the date of the grant. These same participants, if they have met or are not subject to share ownership requirements, may elect to have their award paid as a lump sum cash amount . During the vesting period, dividend equivalents accrue to the participants in the form of additional share units as of each normal cash dividend payment date of Cameco’s common shares. As of December 31, 2020 , the total number of RSUs held by the participants was 927,462, ( 2019 - 4 43,274 ). D. Phantom stock option Cameco makes annual gra nts of bonuses to eligible non-North American employees in the form of phantom stock options. Employees receive the equivalent value of shares in cash when exercised. Options granted under the phantom stock option plan have an award value equal to the clos ing price quoted on the TSX for the common shares of Cameco on the trading day prior to the date on which the option is granted. The options vest over three years and expire eight years from the date granted . As of December 31, 2020 , the number of optio ns held by participating employees was 422,291 ( 2019 - 406,270 ) with exercise prices ranging from $ 11.32 to $ 2 6 .81 per share ( 2019 - $ 11.32 to $ 26.81 ) and a weighted average exercise price of $ 15.66 ( 2019 - $ 16.48 ). E. Employee share ownership p lan Cameco also has an employee share ownership plan, whereby both employee and Company contributions are used to purchase shares on the open market for employees. The Company’s contributions are expensed during the year of contribution. Under the plan, em ployees have the opportunity to participate in the program to a maximum of 6% of eligible earnings each year with Cameco matching the first 3% of employee-paid shares by 50%. Cameco contributes $1,000 of shares annually to each employee that is enrolled in the plan . Shares purchased with Company contributions and with dividends paid on such shares become unrestricted 12 months from the date on which such shares were purchased . At December 31, 2020 , there were 2,257 participants in the plan ( 2019 - 2,2 53 ). The total number of shares purchased in 2020 with Company contributions was 248,837 ( 2019 - 235,915 ). In 2020 , the Company’s contributions totaled $ 3,174,000 ( 2019 - $ 3,127,000 ). F. Deferred share unit (DSU) Cameco offers a DSU plan to n on-employee directors. A DSU is a notional unit that reflects the market value of a single common share of Cameco. 60% of each director’s annual retainer is paid in DSUs. In addition, on an annual basis, directors can elect to receive 25%, 50%, 75% or 100% of the remaining 40% of their annual retainer and any additional fees in the form of DSUs . If a director meets their ownership requirements, the director may elect to take 25%, 50%, 75% or 100% of their annual retainer and any fees in cash, with the balan ce, if any, to be paid in DSUs. Each DSU fully vests upon award . Dividend equivalents accrue to the participants in the form of additional share units as of each normal cash dividend payment date of Cameco’s common shares. The DSUs will be redeemed for cas h upon a director leaving the board. The redemption amount will be based upon the weighted average of the closing prices of the common shares of Cameco on the TSX for the last 20 trading days prior to the redemption date multiplied by the number of DSUs he ld by the director. As of December 31, 2020 , the total number of DSUs held by participating directors was 541,827 ( 2019 - 474,266 ). Equity-settled plans Cameco records compensation expense under its equity-settled plans with an offsetting credit to contributed surplus, to reflect the estimated fair value of units granted to employees. During the year, the Company recognized the following expenses under these plans: 2020 2019 Stock option plan $ 1,011 $ 4,418 Performance share unit plan (a) 2,650 7,245 Restricted share unit plan 2,903 2,679 Employee share ownership plan 3,174 3,127 Total $ 9,738 $ 17,469 (a) In the fourth quarter of 2019, the performance share unit plan was amended to allow eligible participants to elect payout of their grants in cash or shares, provided they have met their share ownership requirements. As a result, this plan is now considered cash-settled for new grants . Expenses related to PSUs granted in previous years will continue to appear as equity-settled if certain assumptions related to the calculation of fair value are met . Fair value measurement of equity-settled plans T he fair value of RSUs granted was determined based on their intrinsic value on the date of grant. Expected volatility was estimated by considering historic average share price volatility. The inputs used in the measurement of the fair values at grant date of the equity-settled RSU plan were as follows: Grant date Mar 1/20 Number of options granted 283,426 Average strike price $11.45 Expected forfeitures 13% Weighted average grant date fair values $11.45 Cash -settled plans Cameco has recognized the following expenses (recoveries) under its cash-settled plans: 2020 2019 Deferred share unit plan $ 3,765 $ (1,001) Performance share unit plan 20,287 - Phantom stock option plan 1,340 (436) Restricted share unit plan (a) 1,849 - Total $ 27,241 $ (1,437) (a) Due to the inclusion of a new group of participants in the RSU plan that are able to elect cash settlement, grants to this group will appear as an expense of a cash-settled plan. Grants to the original group of participants are still disclosed as an expens e of an equity-settled plan . At December 31, 2020 , a liability of $ 38 , 354 ,000 ( 2019 - $ 14,577,000 ) was included in the consolidated statements of financial position to recognize accrued but unpaid expenses for cash-settled plans. Fair value measurem ent of cash-settled plans The fair value of the units granted through the PSU plan was determined based on Monte Carlo simulation and the fair value of RSUs granted was determined based on their intrinsic value on the date of grant. The phantom stock optio n plan was measured based on the Black-Scholes option-pricing model. Expected volatility is estimated by considering historic average share price volatility. The inputs used in the measurement of the fair values of the cash-settled share-based payment plan s at the grant and reporting dates were as follows: PSU RSU Phantom stock options Grant date Reporting date Grant date Reporting date Grant date Reporting date Mar 1/20 Dec 31/20 Mar 1/20 Dec 31/20 Mar 1/20 Dec 31/20 Number of units 636,570 1,720,636 423,180 425,176 112,140 422,291 Expected vesting 102% 129% - - - - Average strike price - - - - $11.61 $15.66 Expected dividend - - - - $0.08 $0.08 Expected volatility (a) - 22% - - 39% 41% Risk-free interest rate (a) - 0.1% - - 0.6% 0.3% Expected life of option 3.0 years 1 year 3.0 years 2.2 years 4 years 3.4 years Expected forfeitures 12% 11% 12% 12% 8% 7% Weighted average measurement date fair values $11.45 $22.01 $11.45 $17.05 $2.85 $5.43 (a) During the first quarter of 2020, the vesting conditions of the PSU plan were amended such that total shareholder return is no longer included for new grants. Due to this change, expected volatility and the risk-free interest rate will no longer be considered in calculating the fair value of new grants. In addition to these inputs, other features of the PSU grant were incorporated into the measurement of fair value. The non-market criteria relating to realized selling prices and operating targets hav e been incorporated into the valuation at both grant and reporting date by reviewing prior history and corporate budgets.

Pension and other post-retireme

Pension and other post-retirement benefits	12 Months Ended
	Dec. 31, 2020
Disclosure Of Defined Benefit Plans [Abstract]
Pension and other post-retirement benefits	25 . Pension and other post-retirement benefits Cameco maintains both defined benefit and defined contribution plans providing pension benefits to substantially all of its employees. All regular and temporary employees participate in a registered defined contribution plan. This plan is registered under the Pension Benefits Standard Act, 1985. In addition, all Canadian-based executives participate in a non-registered supplemental execu tive pension plan which is a defined benefit plan. Under the supplemental executive pension plan (SEPP) , Cameco provides a lump sum benefit equal to the present value of a lifetime pension benefit based on the executive’s length of service and final average earnings. The plan provides for unreduced benefits to be paid at the normal retirement age of 65, however unreduced ben efits could be paid if the executive was at least 60 years of age and had 20 years of service at retirement. This program provides for a benefit determined by a formula based on earnings and service, reduced by the benefits payable under the registered bas e plan. Security is provided for the SEPP benefits through a letter of credit held by the plan’s trustee. The face amount of the letter of credit is determined each year based on the wind-up liabilities of the supplemental plan, less any plan assets curren tly held with the trustee. A valuation is required annually to determine the letter of credit amount. Benefits will continue to be paid from plan assets until the fund is exhausted, at which time Cameco will begin paying benefits from corporate assets. Cam eco also maintains non-pension post-retirement plans (“other benefit plans”) which are defined benefit plans that cover such benefits as group life insurance and supplemental health and dental coverage to elig ible employees and their depende nts. The costs related to these plans are charged to earnings in the period during which the employment services are rendered. These plans are funded by Cameco as benefit claims are made. The board of directors of Cameco has final responsibility and accountability for th e Cameco retirement programs. The board is ultimately responsible for managing the programs to comply with applicable legislation, providing oversight over the general functions and setting certain policies. Cameco expects to pay $ 1 ,785 ,000 in contribution s and letter of credit fees to i ts defined benefit plans in 2021 . The post-retirement plans expose Cameco to actuarial risks, such as longevity risk, market risk, interest rate risk, liquidity risk and foreign currency risk. The other benefit plans expo se Cameco to risks of higher supplemental health and dental utilization than expected. However, the other benefit plans have limits on Cameco’s annual benefits payable. The effective da te of the most recent valuation for funding purposes on the registered defined benefit pension plans is January 1, 2018 . The next planned effective date f or valuations is January 1, 2021 . Cameco has more than one defined benefit plan and has generally provided aggregated disclosures in respect of these plans, on the basis tha t these plans are not exposed to materially different risks. Information relating to Cameco’s defined benefit plans is shown in the following table: Pension benefit plans Other benefit plans 2020 2019 2020 2019 Fair value of plan assets, beginning of year $ 6,806 $ 7,177 $ - $ - Interest income on plan assets 197 262 - - Return on assets excluding interest income 130 280 - - Benefits paid (915) (912) - - Administrative costs paid (1) (1) - - Fair value of plan assets, end of year $ 6,217 $ 6,806 $ - $ - Defined benefit obligation, beginning of year $ 62,588 $ 54,271 $ 24,955 $ 21,161 Current service cost 1,977 1,586 1,010 817 Interest cost 1,673 1,807 792 841 Actuarial loss (gain) arising from: - demographic assumptions - - 102 - - financial assumptions 6,323 6,925 2,013 2,877 - experience adjustment 350 777 (2,236) 114 Benefits paid (1,765) (1,705) (809) (855) Foreign exchange 973 (1,073) - - Defined benefit obligation, end of year $ 72,119 $ 62,588 $ 25,827 $ 24,955 Defined benefit liability [note 14] $ (65,902) $ (55,782) $ (25,827) $ (24,955) The percentages of the total fair value of assets in the pension plans for each asset category at December 31 were as follows: Pension benefit plans 2020 2019 Asset category (a) Canadian equity securities 8% 9% U.S. equity securities 12% 12% Global equity securities 8% 9% Canadian fixed income 31% 30% Other (b) 41% 40% Total 100% 100% (a) The defined benefit plan assets contain no material amounts of related p arty assets at December 31, 2020 and 2019 respectively. (b) Relates mainly to the value of the refundable tax account held by the Canada Revenue Agency. The refundable total is approximately equal to half of the sum of the realized investment income plus employer contributions less half of the benefits paid by the plan . The following represents the components of net pension and other benefit expense included primarily as part of administration: Pension benefit plans Other benefit plans 2020 2019 2020 2019 Current service cost $ 1,977 $ 1,586 $ 1,010 $ 817 Net interest cost 1,476 1,545 792 841 Administration cost 1 1 - - Defined benefit expense [note 18] 3,454 3,132 1,802 1,658 Defined contribution pension expense [note 18] 12,410 11,767 - - Net pension and other benefit expense $ 15,864 $ 14,899 $ 1,802 $ 1,658 The total amount of actuarial losses (gains) recognized in other comprehensive income is: Pension benefit plans Other benefit plans 2020 2019 2020 2019 Actuarial loss (gain) $ 6,673 $ 7,702 $ (121) $ 2,991 Return on plan assets excluding interest income (130) (280) - - $ 6,543 $ 7,422 $ (121) $ 2,991 The assumptions used to determine the Company’s defined benefit obligation and net pension and other benefit expense were as follows at December 31 (expressed as weighted averages): Pension benefit plans Other benefit plans 2020 2019 2020 2019 Discount rate - obligation 2.4% 3.0% 2.5% 3.1% Discount rate - expense 3.0% 3.7% 3.1% 3.9% Rate of compensation increase 2.9% 3.0% - - Initial health care cost trend rate - - 5.0% 6.0% Cost trend rate declines to - - 5.0% 5.0% Year the rate reaches its final level - - 2021 2022 Dental care cost trend rate - - 4.5% 5.0% At December 31, 2020 , the weighted average duration of the defined benefit obligation for the pension p lans was 20 .5 years ( 2019 - 20.0 years) and for the other benefit p lans was 14.2 years ( 2019 - 15.2 years). A 1% change at the reporting date to one of the relevant actuarial assumptions, holding other assumptions constant, would have affected the defined benefit obligation by the following: Pension benefit plans Other benefit plans Increase Decrease Increase Decrease Discount rate $ (9,778) $ 12,766 $ (3,270) $ 4,138 Rate of compensation increase 3,009 (2,772) n/a n/a A 1% change in any of the other assumptions would not have a significant impact on the defined benefit obligation. The methods and assumptions used in preparing the sensitivity analyses are the same as the methods and assumptions used in determining the financial position of Cameco ’s plans as at December 31, 2020 . The sensitivity analyses are determined by varying the sensitivity assumption and leaving all other assumptions unchanged. Therefore, the sensitivity analyses do not recognize any interdependence in the assumptions. The methods and assumptions used in de termining the above sensitivity are consistent with the methods and assumptions used in the previous year. I n addition, an increase of one year in the expected lifetime of plan participants in the pension benefit plans would increase the defined benefit ob ligation by $ 2,030 ,000 . To measure the longevity risk for these plans, the mortality rates were reduced such that the average life expectancy for all members increased by one year. The reduced mortality rates were subsequently used to re-measure the define d benefit obligation of the entire plan.

Financial instruments and relat

Financial instruments and related risk management	12 Months Ended
	Dec. 31, 2020
Disclosure Of Financial Instruments [Abstract]
Financial instruments and related risk management	26 . Financial instruments and related risk management Cameco is exposed in varying degrees to a variety of risks from its use of financial instruments. Management and the board of directors, both separately and together, discuss the principal risks of our businesses. The board sets policies for the implementation of systems to manage, monitor and mitigate identifiable risks. Cameco’s risk management objective in relation to these instruments is to protect and minimize volatility in cash flow. The types of risks Cameco is exposed to, the source of risk exposure and how each is managed is outlined below. Market risk Market risk is the risk that changes in market prices, such as commodity prices, foreign currency exchange rates and interest rates, will aff ect the Company’s earnings or the fair value of its financial instruments. Cameco engages in various business activities which expose the Company to market risk. As part of its overall risk management strategy, Cameco uses derivatives to manage some of its exposures to market risk that result from these activities. Derivative instruments may include financial and physical forward contracts. Such contracts may be used to establish a fixed price for a commodity, an interest-bearing obligation or a cash flow d enominated in a foreign currency. Market risks are monitored regularly against defined risk limits and tolerances. Cameco’s actual exposure to these market risks is constantly changing as the Company’s portfolios of foreign currency , interest rate and comm odity contracts change . The types of market risk exposure and the way in which such exposure is managed are as follows: A. Commodity price risk As a significant producer and supplier of uranium and nuclear fuel processing services, Cameco bears significant exposure to changes in prices for these products. A substantial change in prices will affect the Company’s net earnings and operating cash flows. Prices for Cameco’s products are volatile and are influenced by numerous factors beyond the Compan y’s control, such as supply and demand fundamentals and geopolitical events. Cameco’s sales contracting strategy focuses on reducing the volatility in future earnings and cash flow, while providing both protection against decreases in market price and rete ntion of exposure to future market price increases. To mitigate the risks associated with the fluctuations in the market price for uranium products, Cameco seeks to maintain a portfolio of uranium product sales contracts with a variety of delivery dates an d pricing mechanisms that provide a degree of protection from pricing volatility. B. Foreign exchange risk The relationship between the Canadian and US dollar affects finan cial results of the uranium business as well as the fuel services business. Sales of uranium product, conversion and fuel manufacturing services are routinely denominated in US dollars while production costs are largely denominated in Canadian dollars. Cam eco attempts to provide some protection against exchange rate fluctuations by planned hedging activity designed to smooth volatility. To mitigate risks associated with foreign currency, Cameco enters into forward sales and option contracts to establish a p rice for future delivery of the foreign currency. These foreign currency contracts are not designated as hedges and are recorded at fair value with changes in fair value recognized in earnings. Cameco also has a natural hedge against US currency fluctuatio ns because a portion of its annual cash outlays, including purchases of uranium and conversion services, is denominated in US dollars. Cameco holds a number of financial instruments denominated in foreign currencies that expose the Company to foreign excha nge risk. Cameco measures its exposure to foreign exchange risk on financial instruments as the change in carrying values that would occur as a result of reasonably possible changes in foreign exchange rates, holding all other variables constant. As of the reporting date, the Company has determined its pre-tax exposure to foreign currency exchange risk on financial instruments to be as follows based on a 5 % weakening of the Canadian dollar: Carrying value Currency (Cdn) Gain (loss) Cash and cash equivalents USD $ 86,985 $ 4,349 Accounts receivable USD 136,894 6,845 Accounts payable and accrued liabilities USD (72,576) (3,629) Net foreign currency derivatives USD 40,872 (38,811) A 5% strengthening of the Canadian dollar against the currencies above at December 31, 2020 would have had an equal but opposite effect on the amounts shown above, assuming all other variables remained constant. C. Interest rate risk The Company has a strategy of minimizing its expo sure to interest rate risk by maintaining target levels of fixed and variable rate borrowings. The proportions of outstanding debt carrying fixed and variable interest rates are reviewed by senior management to ensure that these levels are within approved pol icy limits. At December 31, 2020 , the proportion of Cameco’s outstanding debt that carries fixed interest rates is 100 % ( 2019 - 85 %). Cameco wa s exposed to interest rate risk during the year through its interest rate swap contracts whereby fixed r ate payments on a notional amount of $ 150,000,000 of the Series E senior unsecured debentures were swapped for variable rate payments. The Series E swaps were set to terminate on November 14, 2022 however with the early retirement of these debentures, the swaps terminated on November 16 , 2020 (see note 13 ). Under the terms of the swaps, Cameco ma de interest payments based on the three-month Canada Dealer Offered Rate plus an average margin of 1. 2 % and receive d fixed interest payments of 3.75 %. At the time of the termination of the Series E swaps, the fair value of the interest rate swap net asset was $ 7,330,000 . The Series D swaps terminate d on September 2, 2019. At December 31, 2020 , the fair value of Cam eco’s interest rate swap net asset was nil ( 2019 - $ 2,313,000 ) . Counterparty credit risk Counterparty credit risk is associated with the ability of counterparties to satisfy their contractual obligations to Cameco, including both payment and performance. The maximum exposure to credit risk, as represented by the carrying amount of the financial assets, at December 31 was: 2020 2019 Cash and cash equivalents $ 918,382 $ 1,062,431 Short-term investments 24,985 - Accounts receivable [note 6] 166,788 323,430 Derivative assets [note 10] 45,605 10,504 Cash and cash equivalents Cameco held cash and cash equivalents of $ 918 ,000,000 at December 31, 2020 ( 2019 - $ 1,062 ,000,000). Cameco mitigates its credit risk by ensuring that balances are held with counterparties with high credit ratings. The Company monitors the credit rating of its counterparties on a monthly basis and has controls in place to ensure prescribed exposure limits with each counterparty are adhered to. Impairment on cash and cash equivalents has been measured on a 12-month ECL basis and reflects the short maturities of the exposures. The Company considers that its cash and cash equivalents have low credit risk based on the external credit ratings of the counterparties. Cameco has assessed its counterparty credi t risk on cash and cash equivalents by applying historic global default rates to outstanding cash balances based on S&P rating. The conclusion of this assessment is that the loss allowance is insignificant. Accounts receivable Cameco’s sales of uranium product, conversion and fuel manufacturing services expose the Company to the risk of non-payment. Cameco manages the risk of non-payment by monitoring the c redit-worthiness of its customers and seeking pre-payment or other forms of payment security from customers with an unacceptable level of credit risk. A summary of the Company’s exposure to credit risk for trade receivables is as follows: Carrying value Investment grade credit rating $ 160,093 Non-investment grade credit rating 5,961 Total gross carrying amount $ 166,054 Loss allowance - Net $ 166,054 At December 31, 2020 , there were no significant concentrations of credit risk and no amounts were held as collateral. Historically, Cameco has experienced minimal customer defaults and, as a result, considers the credit quality of its accounts receivable to be high. Cameco uses customer credit rating data, historic default rates and aged receivable analysis to measure the ECLs of trade receivables from corporate customers, which comprise a small number of large balances. Since the Company has no t experienced customer defaults in the past, applying historic default rates in calculating ECLs, as well as considering forward-looking information, resulted in an insignificant allowance for losses. The following table provides information about Cameco ’s aged trade receivables as at December 31, 2020 : Corporate Other customers customers Total Current (not past due) $ 159,280 $ 3,649 162,929 1-30 days past due 133 434 567 More than 30 days past due 2,043 515 2,558 Total $ 161,456 $ 4,598 166,054 L iquidity risk Financial liquidity represents Cameco’s ability to fund future operating activities and investments. Cameco ensures that there is sufficient capital in order to meet short-term bu siness requirements, after taking into account cash flows from operations and the Company’s holdings of cash and cash equivalents. The Company believes that these sources will be sufficient to cover the likely short-term and long-term cash requirements. The table below outlines the Company’s available debt facilities at December 31, 2020: Outstanding and Total amount committed Amount available Unsecured revolving credit facility $ 1,000,000 $ - $ 1,000,000 Letter of credit facilities [note 13] 1,698,340 1,596,488 101,852 The tables below present a maturity analysis of Cameco’s financial liabilities, including principal and interest, based on the expected cash flows from the reporting date to the contractual maturity date: Due in Carrying Contractual less than Due in 1-3 Due in 3-5 Due after 5 amount cash flows 1 year years years years Accounts payable and accrued liabilities $ 233,649 $ 233,649 $ 233,649 $ - $ - $ - Long-term debt 995,541 1,000,000 - - 500,000 500,000 Foreign currency contracts 4,733 4,733 1,658 3,075 - - Lease obligation [note 14] 7,951 8,525 3,657 3,896 972 - Total contractual repayments $ 1,241,874 $ 1,246,907 $ 238,964 $ 6,971 $ 500,972 $ 500,000 Due in less than Due in 1-3 Due in 3-5 Due after 5 Total 1 year years years years Total interest payments on long-term debt $ 267,905 $ 37,840 $ 75,680 $ 44,255 $ 110,130 Measurement of fair values A. Accounting classifications and fair values The following tables summarize the carrying amounts and accounting classifications of Cameco’s financial instruments at the reporting date: At December 31, 2020 FVTPL Amortized cost FVOCI - designated Total Financial assets Cash and cash equivalents $ - $ 918,382 $ - $ 918,382 Short-term investments - 24,985 - 24,985 Accounts receivable [note 6] - 204,980 - 204,980 Derivative assets [note 10] Foreign currency contracts 45,605 - - 45,605 Investments in equity securities [note 10] - - 43,873 43,873 $ 45,605 $ 1,148,347 $ 43,873 $ 1,237,825 Financial liabilities Accounts payable and accrued liabilities [note 12] $ - $ 233,649 $ - $ 233,649 Lease obligation [note 14] - 7,951 - 7,951 Derivative liabilities [note 14] Foreign currency contracts 4,733 - - 4,733 Long-term debt [note 13] - 995,541 - 995,541 4,733 1,237,141 - 1,241,874 Net $ 40,872 $ (88,794) $ 43,873 $ (4,049) At December 31, 2019 FVTPL Amortized cost FVOCI - designated Total Financial assets Cash and cash equivalents $ - $ 1,062,431 $ - $ 1,062,431 Accounts receivable [note 6] - 328,044 - 328,044 Derivative assets [note 10] Foreign currency contracts 8,191 - - 8,191 Interest rate contracts 2,313 - - 2,313 Investments in equity securities [note 10] - - 24,408 24,408 $ 10,504 $ 1,390,475 $ 24,408 $ 1,425,387 Financial liabilities Accounts payable and accrued liabilities [note 12] $ - $ 181,799 $ - $ 181,799 Lease obligation - 12,869 - 12,869 Derivative liabilities [note 14] Foreign currency contracts 12,524 - - 12,524 Long-term debt [note 13] - 996,718 - 996,718 12,524 1,191,386 - 1,203,910 Net $ (2,020) $ 199,089 $ 24,408 $ 221,477 Cameco has pledged $ 190 ,140 ,000 of cash as security against certain of its letter of credit facilities. This cash is being used as collateral for an interest rate reduction on the letter of credit facilities. The collateral account has a term of five years effective July 1, 2018. Cameco retains full access to this cash . The investments in equity securities represent investments that Cameco intends to hold for the long-term for strategic purposes. As permitted by IFRS 9, these investments have been designated at the date of initial applic ation as measured at FVOCI. The accumulated fair value reserve related to these investments will never be reclassified to profit or loss. Cameco has not irrevocably des ignated a financial asset that would otherwise meet the requirements to be measured at amortized cost at FVOCI or FVTPL to eliminate or significantly reduce an accounting mismatch that would otherwise arise. The following tables summarize the carrying amou nts and fair values of Cameco’s financial instruments, including their levels in the fair value hierarchy: As at December 31, 2020 Fair value Carrying value Level 1 Level 2 Total Derivative assets [note 10] Foreign currency contracts $ 45,605 $ - $ 45,605 $ 45,605 Investments in equity securities [note 10] 43,873 43,873 - 43,873 Derivative liabilities [note 14] Foreign currency contracts (4,733) - (4,733) (4,733) Long-term debt [note 13] (995,541) - (1,173,280) (1,173,280) Net $ (910,796) $ 43,873 $ (1,132,408) $ (1,088,535) As at December 31, 2019 Fair value Carrying value Level 1 Level 2 Total Derivative assets [note 10] Foreign currency contracts $ 8,191 $ - $ 8,191 $ 8,191 Interest rate contracts 2,313 - 2,313 2,313 Investments in equity securities [note 10] 24,408 24,408 - 24,408 Derivative liabilities [note 14] Foreign currency contracts (12,524) - (12,524) (12,524) Long-term debt [note 13] (996,718) - (1,111,923) (1,111,923) Net $ (974,330) $ 24,408 $ (1,113,943) $ (1,089,535) The preceding tables exclude fair value information for financial instruments whose carrying amounts are a reasonable approximation of fair value. The carrying values of Cameco’s cash and cash equivalents, short-term investments, accounts receivable, and accounts payable and accrued liabilities approximate their fair values as a result of the short-term nature of the instruments. There were no transfers between level 1 and level 2 during the period. Cameco does not have any financial instruments that are classified as level 3 as of the reporting date. B. Financial instruments measured at fair value Cameco measures its derivative financial instruments, material investm ents in equity securities and long-term debt at fair value. Investments in publicly held equity securities are classified as a recurring level 1 fair value measurement while derivative financial instruments and long-term debt are classified as a recurring level 2 fair value measurement. The fair value of investments in equity securities is determined using quoted share prices observed in the principal market for the securities as of the reporting date. The fair value of Cameco’s long-term debt is determine d using quoted market yields as of the reporting date, which ranged from 0.3 % to 1.1 % ( 2019 - 1. 7 % to 1.8 %). Foreign currency derivatives consist of foreign currency forward contracts, options and swaps. The fair value of foreign currency options is me asured based on the Black Scholes option-pricing model. The fair value of foreign currency forward contracts and swaps is measured using a market approach, based on the difference between contracted foreign exchange rates and quoted forward exchange rates as of the reporting date. Interest rate derivatives consist of interest rate swap contracts. The fair value of interest rate swaps is determined by discounting expected future cash flows from the contracts. The future cash flows are determined by measurin g the difference between fixed interest payments to be received and floating interest payments to be made to the counterparty based on Canada Dealer Offer Rate forward interest rate curves. Uranium contract derivatives consist of price swaps. The fair valu e of uranium price swaps is determined by discounting expected future cash flows from the contracts. The future cash flows are determined by measuring the difference between fixed purchases or sales under contracted prices, and floating purchases or sales based on Numerco forward uranium price curves. The swaps were settled during 2019. Where applicable, the fair value of the derivatives reflects the credit risk of the instrument and includes adjustments to take into account the credit risk of the Company a nd counterparty. These adjustments are based on credit ratings and yield curves observed in active markets at the reporting date. Derivatives The following table summarizes the fair value of derivatives and classification on the consolidated statements of financial position: 2020 2019 Non-hedge derivatives: Foreign currency contracts $ 40,872 $ (4,333) Interest rate contracts - 2,313 Net $ 40,872 $ (2,020) Classification: Current portion of long-term receivables, investments and other [note 10] $ 16,466 $ 4,144 Long-term receivables, investments and other [note 10] 29,139 6,360 Current portion of other liabilities [note 14] (1,658) (7,505) Other liabilities [note 14] (3,075) (5,019) Net $ 40,872 $ (2,020) The following table summarizes the different components of the gains (losses) on derivatives included in net earnings: 2020 2019 Non-hedge derivatives: Foreign currency contracts $ 30,600 $ 31,863 Interest rate contracts 5,977 2,068 Uranium contracts - (1,662) Net $ 36,577 $ 32,269

Capital management

Capital management	12 Months Ended
	Dec. 31, 2020
Disclosure of objectives policies and processes for managing capital abstract
Capital management	27 . Capital management Cameco’s management considers its capital structure to consist of bank overdrafts, long-term debt, short-term debt (net of cash and cash equivalents and short-term investments), non-controlling interest and shareholders’ equity . Despite the impacts of COVID-19 on the global economy, Cameco’s approach to capital management has remained consistent. Cameco’ s capital structure reflects its strategy and the environment in which it operate s. Delivering returns to long- term sha reholders is a top priority. The Company’s objective is to maximize cash flow while maintaining its investme nt grade rating through close capital management of our balance sheet metrics. C apital re sources are managed to allow it to support achievement of its goals while managing financial risks such as the continued weakness in the market, litigation risk and re financing risk . The overall objecti ves for managing capital in 2020 reflect the environment that the Company is operating in, similar to the prior comparative period. The capital structure at December 31 was as follows: 2020 2019 Long-term debt [note 13] 995,541 996,718 Cash and cash equivalents (918,382) (1,062,431) Short-term investments (24,985) - Net debt 52,174 (65,713) Non-controlling interest 206 238 Shareholders' equity 4,958,355 4,994,725 Total equity 4,958,561 4,994,963 Total capital $ 5,010,735 $ 4,929,250 Cameco is bound by certain covenants in its general credit facilities. These covenants place restrictions on total debt, including guarantees and set minimum levels for ne t worth. As of December 31, 2020 , Cameco met these requirements.

Segmented information

Segmented information	12 Months Ended
	Dec. 31, 2020
Disclosure Of Operating Segments [Abstract]
Segmented information	28 . Segmented information Cameco has two reportable segments: uranium and fuel services. Cameco's reportable segments are strategic business units with different products, processes and marketing strategies . The uranium segment involves the exploration for, mining, milling, purchase and sale of uranium concentrate. The fuel ser vices segment involves the refining, conversion and fabrication of uranium concentrate and the purchase and sale of conversion services. Cost of sales in the uranium segment includes care and maintenance costs for our operations that currently have produc tion suspensions. Cameco expensed $ 195,972 ,000 ( 2019 - $ 153,924 ,000 ) of care and maintenance c osts during the year . Included in th is amount in 2020 is $ 45 , 988 ,000 relating to care and maintenance costs for operations suspended as a result of COVID-19 . Also included in cost of sales , because of the Cigar Lake production suspension, is the impact of increased purchasing activity at a higher cost than produced pounds . This had a negative impact on gross profit in the uranium segment. Cost of sales in the fuel services segment also includes care and maintenance costs for our operations that have had production suspensions as a result of COVID-19. Cameco expensed $ 8,992,000 in 2020 due to the suspension. Accounting policies used in ea ch segment are consistent with the policies outlined in the summary of significant accounting policies. Segment revenues, expenses and results include transactions between segments incurred in the ordinary course of business. These transactions are priced on an arm’s length basis, are eliminated on consolidation and are reflected in the “other” column. A. Business segments - 2020 For the year ended December 31, 2020 Uranium Fuel services Other Total Revenue $ 1,411,770 $ 377,296 $ 11,007 $ 1,800,073 Expenses Cost of products and services sold 1,244,049 237,656 3,257 1,484,962 Depreciation and amortization 154,560 43,190 10,912 208,662 Cost of sales 1,398,609 280,846 14,169 1,693,624 Gross profit (loss) 13,161 96,450 (3,162) 106,449 Administration - - 145,344 145,344 Exploration 10,873 - - 10,873 Research and development - - 3,965 3,965 Other operating expense 23,921 - - 23,921 Loss on disposal of assets 667 405 - 1,072 Finance costs - - 96,133 96,133 Gain on derivatives - - (36,577) (36,577) Finance income - - (10,835) (10,835) Share of earnings from equity-accounted investee (36,476) - - (36,476) Other income (202) - (51,238) (51,440) Earnings (loss) before income taxes 14,378 96,045 (149,954) (39,531) Income tax expense 13,666 Net loss (53,197) Capital expenditures for the year $ 46,697 $ 30,760 $ 5 $ 77,462 For the year ended December 31, 2019 Uranium Fuel services Other Total Revenue $ 1,413,809 $ 370,277 $ 78,839 $ 1,862,925 Expenses Cost of products and services sold 1,041,922 234,423 69,206 1,345,551 Depreciation and amortization 218,832 45,856 11,061 275,749 Cost of sales 1,260,754 280,279 80,267 1,621,300 Gross profit (loss) 153,055 89,998 (1,428) 241,625 Administration - - 124,869 124,869 Exploration 13,686 - - 13,686 Research and development - - 6,058 6,058 Other operating expense 2,732 - - 2,732 Loss on disposal of assets 1,869 - - 1,869 Finance costs - - 98,622 98,622 Gain on derivatives - - (32,269) (32,269) Finance income - - (29,760) (29,760) Share of earnings from equity-accounted investee (45,360) - - (45,360) Other expense (income) (52,801) - 18,961 (33,840) Earnings (loss) before income taxes 232,929 89,998 (187,909) 135,018 Income tax expense 61,077 Net earnings 73,941 Capital expenditures for the year $ 48,092 $ 27,117 $ 2 $ 75,211 B. Geographic segments Revenue is attributed to the geographic location based on the location of the entity providing the services. The Company’s revenue from external customers is as follows: 2020 2019 United States $ 1,177,756 $ 1,295,195 Canada 622,317 567,730 $ 1,800,073 $ 1,862,925 The Company’s non-current assets, excluding deferred tax assets and financial instruments, by geographic location are as follows: 2020 2019 Canada $ 3,260,144 $ 3,267,376 Australia 421,836 392,500 United States 145,328 121,102 Kazakhstan 55 80 Germany 16 24 $ 3,827,379 $ 3,781,082 C. Major customer s Cameco relies on a small number of customers to purchase a significant portion of its uranium concentrates and uranium conversion services. During 2020 , revenues from two customers of Cameco’s uranium and fuel services segments represented approximately $ 457,560,000 ( 2019 - $ 422,740,000 ), approximately 25 % ( 2019 - 24 %) of Cameco’s total revenues from these segments. As customers are relatively few in number, accounts receivable from any individual customer may peri odically exceed 10% of accounts receivable depending on delivery schedule.

Group entities

Group entities	12 Months Ended
	Dec. 31, 2020
Disclosure Of Significant Investments In Subsidiaries [Abstract]
Group entities	29 . Group entities The following are the principal subsidiaries and associates of the Company: Principal place Ownership interest of business 2020 2019 Subsidiaries: Cameco Fuel Manufacturing Inc. Canada 100% 100% Cameco Marketing Inc. Canada 100% 100% Cameco Inc. US 100% 100% Power Resources, Inc. US 100% 100% Crow Butte Resources, Inc. US 100% 100% NUKEM, Inc. US 100% 100% Cameco Australia Pty. Ltd. Australia 100% 100% Cameco Europe Ltd. Switzerland 100% 100% Associates: JV Inkai Kazakhstan 40% 40%

Joint operations

Joint operations	12 Months Ended
	Dec. 31, 2020
Disclosure Of Joint Operations [Abstract]
Joint operations	30 . Joint operations Cameco conducts a portion of its exploration, development, mining and milling activities through joint operations located around the world. Operations are governed by agreements that provide for joint control of the strategic operating, investing and financing activities among the partners. These agreements were considered in the determination of joint control. Cameco’s significant Canadian uranium joint operation interests are McArthur River, Key Lake and Cigar Lake. The Canad ian uranium joint operations allocate uranium production to each joint operation participant and the joint operation participant derives revenue directly from the sale of such product. Mining and milling expenses incurred by joint operations are included i n the cost of inventory . Cameco reflects its proportionate interest in these assets and liabilities as follows: Principal place of business Ownership 2020 2019 Total assets McArthur River Canada 69.81% $ 1,027,617 $ 1,046,556 Key Lake Canada 83.33% 560,845 524,324 Cigar Lake Canada 50.03% 1,327,956 1,354,399 $ 2,916,418 $ 2,925,279 Total liabilities McArthur River 69.81% $ 34,597 $ 32,132 Key Lake 83.33% 278,331 227,562 Cigar Lake 50.03% 46,604 47,396 $ 359,532 $ 307,090

Related parties

Related parties	12 Months Ended
	Dec. 31, 2020
Disclosure of transactions between related parties [Abstract]
Related parties	31 . Related parties A. Transactions with key management personnel Key management personnel are those persons that have the authority and responsibility for planning, directing and controlling the activities of the Company, directly or indirectly. Key management personnel of the Company include executive officers, vice-presidents, other senior managers and members of the board of directors. In addition to their salaries, Cameco also provides non-cash benefits to executive officers and vice-presidents an d contributes to pensio n plans on their behalf (note 25 ). Senior management and directors also participate in the Company’s share-b ased compensation plans (note 24 ). Executive officers are subject to terms of notice ranging from three to six months. Upon resignation at the Company’s request, they are entitled to termination benefits of up to the lesser of 18 to 24 months or the period remaining until age 65. The termination benefits include gross salary plus the target short-term incentive bonus for t he year in which termination occurs . Compensation for key management personnel was comprised of: 2020 2019 Short-term employee benefits $ 21,676 $ 21,225 Share-based compensation (a) 26,230 12,034 Post-employment benefits 6,041 5,542 Termination benefits 430 272 Total $ 54,377 $ 39,073 (a) Excludes deferred share units held by directors (see note 24). B. Other related party transactions Cameco funded JV Inkai’s project development costs through an unsecured shareholder loan. The limit of the loan facility was $ 175,000 ,000 (US) and advances under the facility b ore interest at a rate of LIB OR plus 2% . At December 31, 2020 , there was no balance outstanding as the loan was fully repaid in 2019 . For the year ended December 31, 2019 , Cameco recorded interest income of $ 1,878,000 relating to this balance. Cameco purchases uranium concentrates from JV Inkai . For the year ended December 31, 2020 , Cameco had purchases of $ 148,169 ,000 ($ 111,886 ,000 (US)) ( 2019 - $ 112,861,000 ($ 84,827,000 (US))) . Cameco received a cash dividend from JV Inkai of $ 54,404,000 ($ 40, 621,000 (US)) ( 2019 - $ 14,079,000 ($ 10,635,000 (US)) ).

Comparative Figures

Comparative Figures	12 Months Ended
	Dec. 31, 2020
Disclosure of reclassifications or changes in presentation [Abstract]
Comparative figures	32 . Comparative Figures Certain prior year balances have been reclassified to conform to the current financial statement presentation .

Significant accounting polici_2

Significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2020
Significant Accounting Policies [Abstract]
Statement of compliance	A. Statement of compliance These consolidated financial statements have been prepared in accordance with International Financial Reporting Standards (IFRS) as issued by the International Accounting Standards Board (IASB). These consolidated financial statements were authorized for issuance by the Company’s board of directors on February 9 , 2021 .
Basis of presentation	B. Basis of presentation These consolidated financial statements are presented in Canadian dollars, which is the Company’s functional currency. All financial information is presented in Canadian dollars , unless otherwise noted. A mounts presented in tabular format have been rounded to the nearest thousand except per share amounts and where otherwise noted. The consolidated financial statements have been prepared on the historical cost ba sis except for the following material items which are measured on an alternative basis at each reporting date: Derivative financial instruments Fair value through profit or loss (FVTPL) Equity investments Fair value through other comprehensive income (FVOCI) Liabilities for cash-settled share-based payment arrangements FVTPL Net defined benefit liability Fair value of plan assets less the present value of the defined benefit obligation The preparation of the consolidated financial statements in conformity with IFRS requires management to make judgments, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets, liabilities, revenue an d expenses. Actual results may vary from these estimates. Estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods aff ected. The areas involving a higher degree of judgment or complexity, or areas where assumptions and estimates are significant to the consolidated financial statements are disclosed in note 5 . This summary of significant accounting policies is a descri ption of the accounting methods and practices that have been used in the preparation of these consolidated financial statements and is presented to assist the reader in interpreting the statements contained herein. These accounting policies have been appli ed consistently to all entities within the consolidated group.
Consolidation principles	C. Consolidation principles
Business combinations	i. Business combinations The acquisition method of accounting is used to account for the acquisition of subsidiaries by the Company. The Company measures goodw ill at the acquisition date as the fair value of the consideration transferred, including the recognized amount of any non-controlling interests in the acquiree, less the net recognized amount (generally fair value) of the identifiable assets acquired and liabilities assumed, all measured as of the acquisition date. When the excess is negative, a bargain purchase gain is recognized immediately in earnings. In a business combination achieved in stages, the acquisition date fair value of the Company’s previou sly held equity interest in the acquiree is also considered in computing goodwill. Consideration transferred includes the fair values of the assets transferred, liabilities incurred and equity interests issued by the Company. Consideration also includes th e fair value of any contingent consideration and share-based compensation awards that are replaced mandatorily in a business combination. The Company elects on a transaction-by-transaction basis whether to measure any non-controlling interest at fair value , or at their proportionate share of the recognized amount of the identifiable net assets of the acquiree, at the acquisition date. Acquisition-related costs are expensed as incurred, except for those costs related to the issue of debt or equity instrument s.
Subsidiaries	ii. Subsidiaries The consolidated financial statements include the accounts of Cameco and its subsidiaries. Subsidiaries are entities over which the Company has control. Subsidiaries are fully consolidated from the d ate on which control is acquired b y the Company and are deconsolidated from the date that control ceases.
Investments in equity-accounted investees	iii. Investments in equity-accounted investees Cameco’s investments in equity-accounted investees include investments in associates . Associates are those entities over which the Comp any has significant influence, but not control or joint control, over the financial and operating policies. Significant influence is presumed to exist when the Company holds between 20% and 50% of the voting power of another entity, but can also arise wher e the Company holds less than 20% if it has the power to be actively involved and influential in policy decisions affecting the entity. Investments in associates are accounted for using the equity method. The equity method involves the recording of the in itial investment at cost and the subsequent adjusting of the carrying value of the investment for Cameco’s proportionate share of the earnings or loss and any other changes in the associates’ net assets, such as dividends. The cost of the investment includ es transaction costs. Adjustments are made to align the accounting policies of the associate with those of the Company before applying the equity method. When the Company’s share of losses exceeds its interest in an equity-accounted investee, the carrying amount of that interest is reduced to zero, and the recognition of further losses is discontinued except to the extent that the Company has incurred legal or constructive obligations or made payments on behalf of the associate. If the associate subsequent ly reports profits, Cameco resumes recognizing its share of those profits only after its share of the profits equals the share of losses not recognized.
Joint arrangements	iv. Joint arrangements A joint arrangement can take the form of a joint operation or joint venture. All joint arrangements involve a contractual arrangement that establishes joint control. A joint operation is a joint arrangement whereby the parties that have joint control of the arrangement have rights to the assets, and obligations for the liabilities , relating to the arrangement. A joint operation may or may not be structured through a separate vehicle. These arrangements involve joint control of one or more of the assets acquired or contributed for the purpose of the joint operation. The consolidated financial statements of the Company include its share of the assets in such joint operations, together with its share of the liabilities, revenues and expenses arising jointly or otherwise from those operations. All such amounts are measured in accordance with the terms of each arrangement. A joint venture is a joint arrangement whereby the parties that have joint control of the arrangement have rights to the net assets of the arrangement. A joint venture is always structured through a separate vehicle. It operates in the same way as other entities, controlling the assets of the joint venture, earning its own revenue and incurring its own liabilities and expenses. Interests in joint ventures are accounted for using the equity method of accounting, whereby t he Company’s proportionate interest in the assets, liabilities, revenues and expenses of jointly controlled entities are recognized on a single line in the consolidated statements of financial position and consolidated statements of earnings. The share of joint ventures results is recognized in the Company’s consolidated financial statements from the date that joint control commences until the date at which it ceases.
Transactions eliminated on consolidation	v. Transactions eliminated on consolidation Intra-group balances and transactions, and any unrealized income and expenses arising from intra-group transactions, are eliminated in preparing the consolidated financial statements. Unrealized gains arising from transactions with equity-accounted investees are eliminated against the investment t o the extent of the Company’s interest in the investee. Unrealized losses are eliminated in the same manner as unrealized gains, but only to the extent that there is no evidence of impairment.
Foreign currency translation	D. Foreign currency translation Items included in the financial statements of each of Cameco’s subsidiaries, associates and joint arrangements are measured using their functional currency, which is the currency of the primary economic environment in which the entity operates. The consoli dated financial statements are presented in Canadian dollars, which is Cameco’s functional and presentation currency. i. Foreign currency transactions Foreign currency transactions are translated into the respective functional currency of the Company a nd its entities using the exchange rates prevailing at the dates of the transactions. At the reporting date, monetary assets and liabilities denominated in foreign currencies are translated to the functional currency at the exchange rate at that date. Non- monetary items that are measured in terms of historical cost in a foreign currency are translated using the exchange rate at the date of the transaction. The applicable exchange gains and losses arising on these transactions are reflected in earnings with the exception of foreign exchange gains or losses on provisions for decommissioning and reclamation activities that are in a foreign currency, which are capitalized in property, plant and equipment. ii. Foreign operations The assets and liabilities of f oreign operations, including goodwill and fair value adjustments arising on acquisition, are translated to Canadian dollars at exchange rates at the reporting dates. The revenues and expenses of foreign operations are translated to Canadian dollars at exch ange rates at the dates of the transactions. Foreign currency differences are recognized in other comprehensive income. When a foreign operation is disposed of, in whole , the relevant amount in the foreign currency translation account is transferred to ear nings as part of the gain or loss on disposal. When the settlement of a monetary item receivable from or payable to a foreign operation is neither planned nor likely in the foreseeable future, foreign exchange gains and losses arising from such a monetary item are considered to form part of the net investment in a foreign operation, and are recognized in other comprehensive income and presented within equity in the foreign currency translation account.
Cash and cash equivalents	E. Cash and cash equivalents Cash and cash equivalent s consists of balances with financial institutions and investments in money market instruments, which have a term to maturity of three months or less at the time of purchase and are measured at amortized cost .
Short-term investments	F. Short-term investment s Short-term investments are comprised of money market instruments with terms to maturity between three and 12 months and are measured at amortized cost.
Inventories	G. Inventories Inventories of broken ore, uranium concentrates, and refined and converted product s are measured at the lower of cost and net realizable value. Cost includes direct materials, direct labour, operational overhead expenses and depreciation. Net realizable value is the estimated selling price in the ordinary course of business, less the es timated costs of completion and selling expenses. Consumable supplies and spares are valued at the lower of cost or replacement value.
Property, plant and equipment	H. Property, plant and equipment
Buildings, plants, equipment	i. Buildings, plant and equipment and other Items of property, plant and equipment are measured at cost less accumulated depreciation and impairment charges. The cost of self-constructed assets includes the cost of materials and direct labour, borrowing costs and any other costs directly attributable to bringing the assets to the locati on and condition necessary for them to be capable of operating in the manner intended by management, including the initial estimate of the cost of dismantling and removing the items and restoring the site on which they are located. When components of an it em of property, plant and equipment have different useful lives, they are accounted for as separate items of property, plant and equipment and depreciated separately. Gains and losses on disposal of an item of property, plant and equipment are determined b y comparing the proceeds from disposal with the carrying amount of property, plant and equipment, and are recognized in earnings.
Mineral properties and mine development costs	ii. Mineral properties and mine development costs The decision to develop a mine property within a project area is based on an assessment of the commercial viability of the property, the availability of financing and the existence of markets for the product. Once the decision to proceed to development is made, development and other expenditures relating to the project area are deferred as part of assets under construction and disclosed as a component of property, plant and equipment with the intention that these will be depreciated by charges against earnings from future mining operations. No depreciation is charged against the property until the production stage commences. After a mine property has been brought into the production stage , costs of any additional work on that property are expensed as incurred, except for large development programs, which will be deferred and depr eciated over the remaining life of the related assets. The production stage is reached when a mine property is in the condition necessary for it to be capable of operating in the manner intended by management. The criteria used to assess the start date of the production stage are determined based on the nature of each mine construction project, including the complexity of a mine site. A range of factors is considered when determining whether the production stage has been reached, which includes, but is not limited to, the demonstration of sustainable production at or near the level intended (such as the demonstration of continuous throughput levels at or above a target percentage of the design capacity).
Depreciation	iii. Depreciation Depreciation is calculated over the depreciable amount, which is the cost of the asset less its residual value. Assets which are unrelated to production are depreciated according to the straight-line method based on estimated useful lives as follows: Land Not depreciated Buildings 15 - 25 years Plant and equipment 3 - 15 years Furniture and fixtures 3 - 10 years Other 3 - 5 years Mining properties and certain mining and conversion assets for which the economic benefits from the asset are consumed in a pattern which is linked to the production level are depreciated according to the unit-of-production method. For conversion assets, the amount of depreciation is measured by the portion of the facilities' total estimated lifetime production that is produ ced in that period. For mining assets and properties, the amount of depreciation or depletion is measured by the portion of the mines' proven and probable mineral reserves recovered during the period. Depreciation methods, useful lives and residual values are reviewed at each reporting period and are adjusted if appropriate.
Borrowing costs	iv. Borrowing costs Borrowing costs on funds directly attributable to finance the acquisition, production or construction of a qualifying asset are capitalized until such time as sub stantially all the activities necessary to prepare the qualifying asset for its intended use are complete. A qualifying asset is one that takes a substantial period of time to prepare for its intended use. Capitalization is discontinued when the asset ente rs the production stage or development ceases. Where the funds used to finance a project form part of general borrowings, interest is capitalized based on the weighted average interest rate applicable to the general borrowings outstanding during the period of construction.
Repairs and maintenance	v. Repairs and maintenance The cost of replacing a component of property, plant and equipment is capitalized if it is probable that future economic benefits embodied within the component will flow to the Company. The carrying amount o f the replaced component is derecognized. Costs of routine maintenance and repair are charged to products and services sold.
Goodwill and intangible assets	I. Goodwill and intangible assets Goodwill arising from the acquisition of subsidiaries is initially recognized at cost, measured as the excess of the fair value of the consideration paid over the fair value of the identifiable net assets acquired . At the date of acquisition, goodwill is allocated to the cash generating unit (CGU), or group of CGUs that is expected to receive the ec onomic benefits of the business combination . Goodwill is subsequently measured at cost, less accumulated impairment losses. Intangible assets acquired individually or as part of a group of assets are initially recognized at cost and measured subsequently a t cost less accumulated amortization and impairment losses. Subsequent expenditure is capitalized only when it increases the future economic benefits embodied in the specific asset to which it relates. The cost of a group of intangible assets acquired in a transaction, including those acquired in a business combination that meet the specified criteria for recognition apart from goodwill, is allocated to the individual assets acquired based on their relative fair values. Intangible assets that have finite us eful lives are amortized over their estimated remaining useful lives. Amortization methods and useful lives are reviewed at each reporting period and are adjusted if appropriate.
Leased assets	J. Lease s Cameco recognizes a right-of-use asset and a lease liability at t he lease commencement date. The right-of-use asset is initially measured at cost, which is the initial amount of the lease liability adjusted for any lease payments made at or before the commencement date, plus any initial direct costs incurred, less any l ease incentives received, and subsequently at cost less any accumulated depreciation and impairment losses. The right-of-use asset is subsequently depreciated using the straight-line method from the commencement date to the end of the lease term, unless th e cost of the right-of-use asset reflect s that the Company will exer cise a purchase option, in which case the right-of-use asset will be deprec iated on the same basis as that of property, plant and equipment . The lease liability is measured at amortized co st using the effective interest method. It is initially measured at the present value of the lease payments that are not paid at the commencement date, discounted using the interest rate implicit in the lease, or, if that rate cannot be readily determined, the Company’s incremental borrowing rate. Generally, Cameco uses its incremental borrowing rate as the discount rate . Current borrowing rates available for classes of leased assets are compared with the rates of Cameco’s existing debt facilities to ensure that use of the Company’s incremental borrowing rate is reasonable. The lease liability is subsequently increased by the interest cost on the lease liability and decreased by lease payments made. It is remeasured when there is a change in future lease pay ments arising from a change in an index or rate, a change in the estimate of the amount expected to be payable under a residual value guarantee, or as appropriate, changes in the assessment of whether a purchase or extension option is reasonably certain to be exercised or a termination option is reasonably certain not to be exercised . Cameco uses judgement in determining the lease term for some lease contracts that include renewal options. The assessment of whether the Company is reasonably certain to exerc ise such options impacts the lease term, which affects the amount of lease liabilities and right-of-use assets recognized . The Company has elected not to recognize right-of-use assets and lease liabilities for leases of low-value assets and short-term leas es that have a lease term of 12 months or less. The lease payments associated with these leases are recognized as an expense on a straight-line basis over the lease term .
Finance income and finance costs	K. Finance income and finance costs Finance income comprises interest income on f unds invested . Interest income and interest expense are recognized in earnings as they accrue , using the effective interest method. Finance costs comprise interest and fees on borrowings, unwinding of the discount on provisions and costs incurred on redemp tion of debentures . Borrowing costs that are not directly attributable to the acquisition, construction or production of a qualifying asset are expensed in the period incurred.
Research and development costs	L. Research and development costs Expenditures on research are charged agains t earnings when incurred. Development costs are recognized as assets when the Company can demonstrate technical feasibility and that the asset will generate probable future economic benefits.
Impairment	M. Impairment
Non-derivative financial assets	i . Non-derivative financial assets Cameco r ecognizes loss allowances for expected credit losses (ECLs) on financial assets measured at amortized cost, debt investments measured at FVOCI, and contract assets. It measures loss allowances at an amount equal to lifetime ECLs, except for debt securities that are determined to have low credit risk at the reporting date and other debt securities, loans advanced and bank balances for which credit risk has not increased significantly since initial recognition. For these, loss allowances are measured equal to 12-month ECLs. Lifetime ECLs are the ECLs that result from all possible default events over the expected life of a financial instrument while 12-month ECLs are the portion of ECLs that result from default events that are possible within the 12 months after the reporting date (or a shorter period if the expected life of the instrument is less than 12 months). The maximum period considered when estimating ECLs is the maximum contractual period over which the Company is exposed to credit risk. ECLs are a probability-weighted estimate of credit losses. Credit losses are m easured as the present value of the difference between the cash flows due to the entity in accordance with the contract and the cash flows that the Company expects to receive. ECLs are discounted at the effective interest rate of the financial asset. When determining whether the credit risk of a financial asset has increased significantly since initial recognition and when estimating ECLs, the Company considers reasonable and supportable information that is relevant and available without undue cost or effor t. This includes both quantitative and qualitative information and analysis, based on the Company’s historical experience and informed credit assessment and including forward-looking information. The Company considers a financial asset to be in default whe n the borrower is unlikely to pay its credit obligations in full, without recourse by Cameco to actions such as realizing security (if any is held). The Company considers a debt security to have low credit risk when it is at least an A (low) DBRS or A- S&P rating. Financial assets carried at amortized cost and debt securities at FVOCI are assessed at each reporting date to determine whether they are ‘credit-impaired’ . A financial asset is ‘credit-impaired’ when one or more events that have a detrimental eff ect on the estimated future cash flows of the financial asset have occurred. E vidence can include significant financial difficulty of the borrower or issuer , a breach of contract, restructuring of an amount due to the Company on terms that the Company woul d not consider otherwise, indications that a debtor or issuer will enter bankruptcy or other financial reorganization , or the disappearance of an active market for a security . Loss allowances for financial assets measured at amortized cost are deducted fro m the gross carrying amount of the assets. For debt securities at FVOCI, the loss allowance is charged to earnings and is recognized in OCI. The gross carrying amount of a financial asset is written off when the Company has no reasonable expectations of re covering a financial asset in its entirety or a portion thereof .
Non-financial assets	ii. Non-financial assets The carrying amounts of Cameco’s non-financial assets are reviewed at each reporting date to determine whether there is any indication of impairment. If any such i ndication exists, then the asset’s recoverable amount is estimated. Goodwill is tested annually for impairment. For impairment testing, assets are grouped together into CGUs which are the smallest group of assets that generate cash inflows from continuing use that are largely independent of the cash inflows of other assets or CGUs. Goodwill arising from a business combination is allocated to CGUs or groups of CGUs that are expected to benefit from the synergies of the combination. The recoverable amount of an asset or CGU is the greater of its value in use and its fair value less costs to sell. Value in use is based on the estimated future cash flows, discounted to their present value using a pre-tax discount rate that reflects current market assessments of the time value of money and the risks specific to the asset or CGU. Fair value is determined as the amount that would be obtained from the sale of the asset or CGU in an arm’s-length transaction between knowledgeable and willing parties. For exploration p roperties, fair value is based on the implied fair value of the resources in place using comparable market transaction metrics. An impairment loss is recognized if the carrying amount of an asset or its CGU exceeds its recoverable amount. Impairment losses are recognized in earnings. Impairment losses recognized in respect of CGUs are allocated first to reduce the carrying amount of any goodwill allocated to the CGU, and then to reduce the carrying amounts of the other assets in the CGU on a pro rata basis. Impairment losses recognized in prior periods are assessed at each reporting date whenever events or changes in circumstances indicate that the impairment may have reversed. If the impairment has reversed, the carrying amount of the asset is increased to its recoverable amount. An impairment loss is reversed only to the extent that the asset’s carrying amount does not exceed the carrying amount that would have been determined, net of depreciation or amortization, if no impairment loss had been recognized. A reversal of an impairment loss is recognized immediately in earnings. An impairment loss in respect of goodwill is not reversed.
Exploration and evaluation expenditures	N. Exploration and evaluation expenditures Exploration and evaluation expenditures are those expenditures incurred by the C ompany in connection with the exploration for and evaluation of mineral resources before the technical feasibility and commercial viability of extracting a mineral resource are demonstrable. These expenditures include researching and analyzing existing exp loration data, conducting geological studies, exploratory drilling and sampling, and compiling prefeasibility and feasibility studies. Exploration and evaluation expenditures are charged against earnings as incurred, except when there is a high degree of c onfidence in the viability of the project and it is probable that these costs will be recovered through future development and exploitation. The technical feasibility and commercial viability of extracting a resource is considered to be determinable based on several factors, including the existence of proven and probable reserves and the demonstration that future economic benefits are probable. When an area is determined to be technically feasible and commercially viable, the exploration and evaluation assets attributable to that area are first tested for impairment and then transferred to property, plant and equipment. Exploration and evaluation costs that have been acquired in a business combination or asset acquisition are capitalized u nder the scope of IFRS 6, Exploration for and Evaluation of Mineral Resources , and are reported as part of property, plant and equipment.
Provisions	O. Provisions A provision is recognized if, as a result of a past event, the Company has a present legal or construc tive obligation that can be estimated reliably, and it is probable that an outflow of economic benefits will be required to settle the obligation. Provisions are determined by discounting the risk-adjusted expected future cash flows at a pre-tax risk-free rate that reflects current market assessments of the time value of money. The unwinding of the discount is recognized as a finance cost .
Environmental restoration	i . Environmental restoration The mining, extraction and processing activities of the Company normally give rise to obligations for site closure and environmental restoration. Closure and restoration can include facility decommissioning and dismantling, removal or treatment of waste materials, as well as site and land restoration. The Company provides for the closure, r eclamation and decommissioning of its operating sites in the financial period when the related environmental disturbance occurs, based on the estimated future costs using information available at the reporting date. Costs included in the provision comprise all closure and restoration activity expected to occur gradually over the life of the operation and at the time of closure. Routine operating costs that may impact the ultimate closure and restoration activities, such as waste material handling conducted as a normal part of a mining or production process, are not included in the provision. The timing of the actual closure and restoration expenditure is dependent upon a number of factors such as the life and nature of the asset, the operating licence condit ions and the environment in which the mine operates. Closure and restoration provisions are measured at the expected value of future cash flows, discounted to their present value using a current pre-tax risk-free rate. Significant judgments and estimates a re involved in deriving the expectations of future activities and the amount and timing of the associated cash flows. At the time a provision is initially recognized, to the extent that it is probable that future economic benefits associated with the recla mation, decommissioning and restoration expenditure will flow to the Company, the corresponding cost is capitalized as an asset. The capitalized cost of closure and restoration activities is recognized in property, plant and equipment and depreciated on a unit-of-production basis. The value of the provision is gradually increased over time as the effect of discounting unwinds. The unwinding of the discount is an expense recognized in finance costs. Closure and rehabilitation provisions are also adjusted for changes in estimates. The provision is reviewed at each reporting date for changes to obligations, legislation or discount rates that effect change in cost estimates or life of operations. The cost of the related asset is adjusted for changes in the provi sion resulting from changes in estimated cash flows or discount rates, and the adjusted cost of the asset is depreciated prospectively.
Waste disposal	ii. Waste disposal The refining, conversion and manufacturing processes generate certain uranium-contaminated waste. The Company has established strict procedures to ensure this waste is disposed of safely. A provision for waste disposal costs in respect of these materials is recognized when they are generated. Costs associated with the disposal, the timing of cash flows and discount rates are estimated both at initial recognition and subsequent measurement.
Employee future benefits	P. Employee future benefits
Pension obligations	i . Pension obligations The Company accrues its obligations under employee benefit plans. The Company has both defined benefit and defined contribution plans. A defined contribution plan is a pension plan under which the Company pays fixed contributions into a separate entity. The Company has no legal or constructive obligations to pay further contributions if the fund does not hold s ufficient assets to pay all employees the benefits relating to employee service in the current and prior periods. A defined benefit plan is a pension plan other than a defined contribution plan. Typically, defined benefit plans define an amount of pension benefit that an employee will receive on retirement, usually dependent on one or more factors such as age, years of service and compensation. The liability recognized in the consolidated statements of financial position in respect of defined benefit pensio n plans is the present value of the defined benefit obligation at the reporting date less the fair value of plan assets. The defined benefit obligation is calculated annually, by qualified independent actuaries using the projected unit credit method prorat ed on service and management's best estimate of expected plan investment performance, salary escalation, retirement ages of employees and expected health care costs. The present value of the defined benefit obligation is determined by discounting the estim ated future cash outflows using interest rates of high-quality corporate bonds that are denominated in the currency in which the benefits will be paid, and that have terms to maturity approximating the terms of the related pension liability. The Company r ecognizes all actuarial gains and losses arising from defined benefit plans in other comprehensive income, and reports them in retained earnings. When the benefits of a plan are improved, the portion of the increased benefit relating to past service by emp loyees is recognized immediately in earnings. For defined contribution plans, the contributions are recognized as employee benefit expense in earnings in the periods during which services are rendered by employees. Prepaid contributions are recognized as a n asset to the extent that a cash refund or a reduction in future payments is available.
Other post-retirement benefits plans	ii. Other post-retirement benefit plans The Company provides certain post-retirement health care benefits to its retirees. The entitlement to these benefits is usua lly conditional on the employee remaining in service up to retirement age and the completion of a minimum service period. The expected costs of these benefits are accrued over the period of employment using the same accounting methodology as used for defin ed benefit pension plans. Actuarial gains and losses are recognized in other comprehensive income in the period in which they arise. These obligations are valued annually by independent qualified actuaries.
Short-term employee benefits	iii. Short-term employee benefits Short-term em ployee benefit obligations are measured on an undiscounted basis and are expensed as the related service is provided. A liability is recognized for the amount expected to be paid under short-term cash bonus plans if the Company has a present legal or const ructive obligation to pay this amount as a result of past service provided by the employee, and the obligation can be measured reliably.
Explanation of termination benefits	iv. Termination benefits Termination benefits are payable when employment is terminated by the Company before the no rmal retirement date, or whenever an employee accepts an entity’s offer of benefits in exchange for termination of employment. Cameco recognizes termination benefits as an expense at the earlier of when the Company can no longer withdraw the offer of those benefits and when the Company recognizes costs for a restructuring. If benefits are payable more than 12 months after the reporting period, they are discounted to their present value.
Share-based compensation	v. Share-based compensation For equity-settled plans, the grant dat e fair value of share-based compensation awards granted to employees is recognized as an employee benefit expense, with a corresponding increase in equity, over the period that the employees unconditionally become entitled to the awards. The amount recogni zed as an expense is adjusted to reflect the number of awards for which the related service and vesting conditions are expected to be met, such that the amount ultimately recognized as an expense is based on the number of awards that meet the related servi ce and non-market performance conditions at the vesting date. For cash-settled plans, the fair value of the amount payable to employees is recognized as an expense, with a corresponding increase in liabilities, over the period that the employees unconditio nally become entitled to payment. The liability is re - measured at each reporting date and at settlement date. Any changes in the fair value of the liability are recognized as employee benefit expense in earnings. When the terms and conditions of equit y-set tled plans at the time they were granted are subsequently modified, the fair value of the share-based payment under the original terms and conditions and under the mod ified terms and conditions are both determined at the date of the modification. Any excess of the modified fair value over the original fair value is recognised over the remaining vesting period in addition to the grant date fair value of the original share-based payment. The share-based payment expense is not ad justed if the modified fair value is less than the original fair value . Cameco’s contributions under the employee share ownership plan are expensed during the year of contribution. Shares purchased with Company contributions and with dividends paid on such shares become unrestricted on January 1 of the second plan year following the date on which such shares were purchased.
Revenue recognition	Q. Revenue recognition Cameco su pplies uranium concentrates, uranium conversion services , fabrication services and other services . Re venue is measured based on the consideration specified in a contract with a customer. The Company recognizes revenue when it transfers control, as described below, over a good or service to a customer. Customers do not have the right to return products. Ca meco’s sales arrangements with its customers are pursuant to enforceable contract s that indicate the nature and timing of satisfaction of performance obligations, including significant payment terms, where payment is usually due in 30 days . Each delivery i s considered a separate performance obligation under the contract. Uranium supply In a uranium supply arrangement, Cameco is contractually obligated to provide uranium concentrates to its cus tomers. Cameco-owned uranium may be physically delivered to eithe r the customer or to conversion facilities (Converters) . For deliveries to customers, terms in the sales contract specify the location of delivery. Revenue is recognized when the uranium has been delivered and accepted by the customer at that location. Whe n uranium is delivered to Converters, the Converter will credit Cameco’s account for the volume of accepted uraniu m. Based on delivery terms in the sales contract with its customer, Cameco instructs the Converter to transfer title of a contractually specif ied quantity of uranium to the customer’s account at the Conver ter’s facility. At this point, control has been transferred and C ameco recognizes revenue for the uranium supply. Toll conversion services In a toll conversion arrangement, Cameco is contractua lly obligated to convert customer-owned uranium to a chemical state suitable for enrichment. Based on delivery terms in a sales contract with its customer, Cameco either ( i ) physically delivers converted uranium to enrichment facilities (Enrichers) where i t instructs the Enricher to transfer title of a contractually specified quantity of converted uranium to the customer’s account at the Enricher’s facility, or (ii) transfers title of a contractually specified quantity of converted uranium to either an Enri cher’s account or the customer’s account at Cameco’s Port Hope conversion facility . At this point, the customer obtains control and C ameco recognizes revenue for the toll conversion services. Conversion supply A conversion supply arrangement is a combination of uranium supply and toll conversion services. Cameco is contractually obligated to provide converte d uranium to its customer s. Based on delivery terms in the sales contract , Cameco either ( i ) physically del ivers converted uranium to the Enricher where it instructs the Enricher to transfer title of a contractually specified quantity of converted uranium to the customer’s account at the Enricher’s facility, or (ii) transfers title of a contractually specified quantity of converted uranium to either an Enricher’s account or a customer’s account at Cameco’s Port Hope conversion facility. At this point, the customer obtains control and Cameco recognizes revenue for both the uranium supplied and the conversion serv ice provided . Fabrication services In a fabrication services arrangement, Cameco is contractually obligated to provide fuel bundles or reactor components to its customers. In a contract for fuel bundles, the bundles are inspected and accepted by the custom er at Cameco’s Port Hope fabrication facility or another location based on delivery terms in the sales contract. At this point, the customer obtains control and Cameco recognizes revenue for the fabrication services. In some contracts for reactor component s, the components are made to a customer’s specification and if a contract is terminated by the customer, Cameco is entitled to reimbursement of the costs incurred to date, including a reasonable margin. Since the customer controls all of the work in progr ess as the products are being manufactured, revenue and associated costs are recognized over time, before the goods are delivered to the customer’s premises. Revenue is recognized on the basis of units produced as the contracts reflect a per unit basis. Re venue from these contracts represents an insignificant portion of Cameco’s total revenue. In other contracts where the reactor components are not made to a specific customer’s specification, when the components are delivered to the location specified in th e contract, the customer obtains control and Cameco recognizes revenue for the services. Other services Uranium concentrates and converted uranium are regulated products and can only be stored at regulated facilities. In a storage arrangement, Cameco is contractually obligated to store uranium products at its facilities on behalf of the customer. Cameco invo ices the customer in accordance with the contract terms and recognizes revenue on a monthly basis . Cameco also provides customers with transportation of its uranium products. In the contractual arrangements where Cameco is acting as the principal, revenue is recognized as the product is delivered .
Financial instruments	R. Financial instruments A financial instrument is any contract that gives rise to a financial asset of one entity and a financial liability or equity instrument of another . Trade receivables and debt securities are initially recognized when they are originated. All other financial assets and liabilities are initially recognized when the company becomes a party to the contractual provisions of the instrument. A financial asset (unless it is a trade receivable wit hout a significant financing component) or financial liability is initially measured at fair value plus, for an item not at fair value through profit or loss, transaction costs that are directly attributable to its acquisition or issue. A trade receivable without a significant financing component is initially measured at the transaction price .
Non-derivative financial assets and financial liabilities	i . Financial assets On initial recognition , financial assets are classified as measured at : amortized cost, fair value through other comprehensive income, or fair value through profit or loss based on the Company’s business model for managing its financial assets and their cash flow characteristics. Classifications are not changed subsequent to initial recognition unless the Company changes its business model for m anaging its financial assets, in which case all affected financial assets are reclassified on the first day of the first reporting period following the change in business model. Amortized cost A financial asset is measured at amortized cost if it is not de signated as at fair value through profit or loss, is held within a business model whose objective is to hold assets to collect contractual cash flows and its contractual terms give rise to cash flows on specified dates that are solely payments of principal and interest on the principal amount outstanding . Assets in this category are subsequently measured at amortized cost using the effective interest method. The amortized cost is reduced by impairment losses. Interest income, foreign exchange gains and loss es and impairment are recognized in profit or loss, as is any gain or loss on derecognition. Fair value through other comprehensive income (FVOCI) A debt investment is measured at FVOCI if it is not designated as at fair value through profit or loss, is he ld within a business model whose objective is achieved by both collecting contractual cash flows and selling financial assets and its contractual terms give rise to cash flows on specified dates that are solely payments of principal and interest on the pri ncipal amount outstanding . These assets are subsequently measured at fair value . Interest income calculated using the effective interest method, foreign exchange gains and losses and impairment are recognized in profit or loss. Other net gains and losses a re re cognized in other comprehensive income (OCI) . On derecognition, gains and losses accumulated in OCI are reclassified to profit or loss. On initial recognition of an equity investment that is not held for trading, Cameco may irrevocably elect to presen t subsequent changes in the investments fair value in OCI. This election is made on an investment by investment basis. These assets are subsequently measured at fair value. Dividends are recognized as income in profit or loss unless the dividend clearly re presents a recovery of part of the cost of the investment. Other net gains and losses are recognized in OCI and are never reclassified to profit or loss. Fair value through profit or loss (FVTPL) All financial assets not classified as measured at amortized cost or FVOCI are measured at FVTPL . This includes all derivative financial asset s. On initial recognition, the C ompany may irrevocably designate a financial asset that otherwise meets the requirements to be measured at amortized cost or at FVOCI as at FV TPL if doing so eliminates or significantly reduces an accounting mismatch that would otherwise arise. These assets are subsequently measured at fair value. Net gains and losses, including any interest or dividend income, are recognized in profit or loss. Derecognition of financial assets Cameco derecognizes a financial asset when the contractual rights to the cash flows from the asset expire, or it transfers the rights to receive the contractual cash flows in a transaction in which substantially all of the risks and rewards of ownership of the financial asset are transferred or in which it neither transfers or retains substantially all of the risks and rewards of ownership and it does not retain control of the financial asset. If the Company enters into a transaction whereby it transfers assets recognized in its statement of financial position, but retains either all or substantially all of the risks and rewards of the transferred assets, the transferred assets would not be dere cognized. ii. Financial liabilitie s On initi al recognition, financial liabilities are classified as measured at amortized cost or FVTPL . A financial liability is classified as FVTPL if it is classified as held-for- trading, is a derivative or is design ated as such on initial recognition. Financial liabilities at FVTPL are measured at fair value and net gains and losses, including any interest expense, are recognized in profit or loss. Other financial liabilities are subsequently measured at amortized co st using the effective interest method. Interest expense and foreign exchange gains and losses are recognized in profit or loss as is any gain or loss on derecognition. A financial liability is derecognized when its contractual obligations are discharged o r cancelled, or expire. The Company also derecognizes a financial liability when its terms are modified and the cash flows of the modified liability are substantially different, in which case a new financial liability based on the modified terms is recogni zed at fair value. On derecognition of a financial liability, the difference between the carrying amount extinguished and the consideration paid (including any non-cash assets transferred or liabilities assumed) is recognized in profit or loss.
Derivative financial instruments	iii. Der ivative financial instruments The Company holds derivative financial instruments to reduce exposure to fluctuations in foreign currency exchange rates and interest rates. Embedded derivatives are separated from the host contract and accounted for separatel y if the host contract is not a financial asset and certain criteria are met. D erivative fi nancial instruments are initially measured at fair value in the consolidated statements of financial position, with any directly attributable transact ion costs recog nized in profit or loss as incurred. Subsequent to initial recognition, derivatives are measured at fair value, and changes in fair value are recognized in profit or loss . The purpose of hedging transactions is to modify the Company’s exposure to one or mo re risks by creating an offset between changes in t he fair value of, or the cash flows attributable to, the hedged item and the hedging item. When hedge accounting is appropriate, the hedging relationship is designated as a fair value hedge, a cash flow he dge, or a foreign currency risk hedge related to a net investment in a foreign operation. The Company does not have any instruments that have been designated as hedge transactions at December 31, 2020 and 2019 .
Income tax	S. Income tax Income tax expense is c omprised of current and deferred taxes. Current tax and deferred tax are recognized in earnings except to the extent that it relates to a business combination, or items recognized directly in equity or in other comprehensive income. Current tax is the expe cted tax payable or receivable on the taxable income or loss for the year, using tax rates enacted or substantially enacted at the reporting date, and any adjustments to tax payable in respect of previous years. Current tax assets and liabilities are measu red at the amount expected to be paid or recovered from the taxation authorities. Deferred tax is recognized in respect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used fo r taxation purposes. In addition, deferred tax is not recognized for taxable temporary differences arising on the initial recognition of goodwill. Deferred tax is measured at the tax rates that are expected to be applied to temporary differences when they reverse, based on the laws that have been enacted or substantively enacted by the reporting date. Deferred tax assets and liabilities are offset if there is a legally enforceable right to offset current tax liabilities and assets, and they relate to income taxes levied by the same tax authority on the same taxable entity, or on different tax entities, but they intend to settle current tax liabilities and assets on a net basis or their tax assets and liabilities will be realized simultaneously. A deferred ta x asset is recognized for unused tax losses, tax credits and deductible temporary differences, to the extent that it is proba ble that future taxable income will be available against which they can be utilized. Deferred tax assets are reviewed at each repor ting date and are reduced to the extent that it is no longer probable that the related tax benefit will be realized. The Company’s exposure to uncertain tax positions is evaluated and a provision is made where it is probable that this exposure will materia lize.
Share capital	T. Share capital Common shares are classified as equity. Incremental costs directly attributable to the issue of common shares are recognized as a reduction of equity, net of any tax effects.
Segment reporting	V. Segment reporting An operating segment is a component of the Company that engages in business activities from which it may earn revenues and incur expenses, including revenues and expenses that relate to transactions with any of the Company’s other segments. To be classifie d as a segment, discrete financial information must be available and operating results must be regularly reviewed by the Company’s executive team . Segment capital expenditure is the total cost incurred during the period to acquire property, plant and equipment, and intangible assets other than goodwill.
Earnings per share	U. Earnings per share The Company presents basic and d iluted earnings per share data for its common shares. Earnings per share is calculated by dividing the net earnings attributable to equity holders of the Company by the weighted average number of common shares outstanding. Diluted earnings per share is det ermined by adjusting the net earnings attributable to equity holders of the Company and the weighted average number of common shares outstanding, for the effects of all dilutive potential common shares. The calculation of diluted earnings per share assumes that outstanding options which are dilutive to earnings per share are exercised and the proceeds are used to repurchase shares of the Company at the average market price of the shares for the period. The effect is to increase the number of shares used to calculate diluted earnings per share.
Government assistance	W. Government assistance Government grants are recognized when there is reasonable assurance tha t the Company has complied with the relevant conditions of the grant and that the grant will be received. Grants that compensate the Company for expenses incurred are recognized in profit or loss as other income on a systematic basis in the periods in which the expenses have been recognized .

Significant accounting polici_3

Significant accounting policies (Table)	12 Months Ended
	Dec. 31, 2020
Significant Accounting Policies [Abstract]
Basis of presentation	Derivative financial instruments Fair value through profit or loss (FVTPL) Equity investments Fair value through other comprehensive income (FVOCI) Liabilities for cash-settled share-based payment arrangements FVTPL Net defined benefit liability Fair value of plan assets less the present value of the defined benefit obligation
Disclosure of estimated useful lives	Land Not depreciated Buildings 15 - 25 years Plant and equipment 3 - 15 years Furniture and fixtures 3 - 10 years Other 3 - 5 years

Accounts receivable (Tables)

Accounts receivable (Tables)	12 Months Ended
	Dec. 31, 2020
Trade And Other Receivables [Abstract]
Schedule of accounts receivable	2020 2019 Trade receivables $ 166,054 $ 321,638 GST/VAT receivables 38,192 4,614 Other receivables 734 1,792 Total $ 204,980 $ 328,044

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2020
Classes Of Inventories [Abstract]
Schedule of Inventories	2020 2019 Uranium Concentrate $ 579,653 $ 204,123 Broken ore 45,387 51,094 625,040 255,217 Fuel services 52,273 62,701 Other 3,056 2,852 Total $ 680,369 $ 320,770

Property, plant and equipment (

Property, plant and equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property Plant And Equipment [Abstract]
Schedule of Property plant and equipment table	At December 31, 2020 Land Plant Furniture Exploration and and and Under and buildings equipment fixtures construction evaluation Total Cost Beginning of year $ 5,050,115 $ 2,678,165 $ 80,869 $ 132,457 $ 1,071,840 $ 9,013,446 Additions 2,030 7,097 855 67,477 3 77,462 Transfers 37,971 21,405 2,554 (60,391) - 1,539 Change in reclamation provision [note 15] 151,558 - - - - 151,558 Disposals (1,678) (3,385) (5,299) (492) (99) (10,953) Effect of movements in exchange rates (15,663) (3,438) (68) - 53,739 34,570 End of year 5,224,333 2,699,844 78,911 139,051 1,125,483 9,267,622 Accumulated depreciation and impairment Beginning of year 2,936,088 1,793,049 76,601 36,799 458,386 5,300,923 Depreciation charge 84,261 89,550 3,010 - - 176,821 Change in reclamation provision [note 15] (a) 23,921 - - - - 23,921 Disposals (903) (2,997) (5,299) (1) (150) (9,350) Effect of movements in exchange rates (12,075) (3,266) (66) - 25,427 10,020 End of year 3,031,292 1,876,336 74,246 36,798 483,663 5,502,335 Right-of-use assets Beginning of year 2,646 5,084 419 - - 8,149 Additions 75 22 2,124 - - 2,221 Disposals (40) (747) - - - (787) Depreciation charge (875) (498) (401) - - (1,774) Transfers - (1,539) - - - (1,539) End of year 1,806 2,322 2,142 - - 6,270 Net book value at December 31, 2020 $ 2,194,847 $ 825,830 $ 6,807 $ 102,253 $ 641,820 $ 3,771,557 At December 31, 2019 Land Plant Furniture Exploration and and and Under and buildings equipment fixtures construction evaluation Total Cost Beginning of year $ 5,039,313 $ 2,654,944 $ 80,083 $ 114,060 $ 1,121,061 $ 9,009,461 Additions 2,327 7,179 158 65,482 65 75,211 Transfers 17,157 28,453 951 (46,561) - - Change in reclamation provision 24,883 - - - - 24,883 Disposals (923) (3,486) (142) (507) (693) (5,751) Effect of movements in exchange rates (32,642) (8,925) (181) (17) (48,593) (90,358) End of year 5,050,115 2,678,165 80,869 132,457 1,071,840 9,013,446 Accumulated depreciation and impairment Beginning of year 2,835,037 1,697,178 74,860 36,799 483,661 5,127,535 Depreciation charge 128,579 105,700 2,057 - - 236,336 Change in reclamation provision (a) 2,732 - - - - 2,732 Disposals (225) (2,194) (139) - (639) (3,197) Effect of movements in exchange rates (30,035) (7,635) (177) - (24,636) (62,483) End of year 2,936,088 1,793,049 76,601 36,799 458,386 5,300,923 Right-of-use assets Beginning of year - - - - - - Additions 3,517 5,768 851 - - 10,136 Disposals - (9) - - - (9) Depreciation charge (871) (675) (432) - - (1,978) End of year 2,646 5,084 419 - - 8,149 Net book value at December 31, 2019 $ 2,116,673 $ 890,200 $ 4,687 $ 95,658 $ 613,454 $ 3,720,672 (a) Asset retirement obligation assets are adjusted when the Company updates its reclamatio n provisions due to new cash flow estimates or changes in discount and inflation rates. When the assets of an operation have been written off due to an impairment, as is the case with our Rabbit Lake operation and some of our operations in the United States , the adjustment is recorded directly to the statement of earnings as other operating expense or income .

Intangible assets (Tables)

Intangible assets (Tables)	12 Months Ended
	Dec. 31, 2020
Intangible Assets And Goodwill [Abstract]
Reconciliation of carrying amount of goodwill and intangibles	At December 31, 2020 Intellectual Contracts property Total Cost Beginning of year $ 113,707 $ 118,819 $ 232,526 Effect of movements in exchange rates (2,319) - (2,319) End of year 111,388 118,819 230,207 Accumulated amortization and impairment Beginning of year 111,094 61,022 172,116 Amortization charge 1,008 3,700 4,708 Effect of movements in exchange rates (2,439) - (2,439) End of year 109,663 64,722 174,385 Net book value at December 31, 2020 $ 1,725 $ 54,097 $ 55,822 At December 31, 2019 Intellectual Contracts property Total Cost Beginning of year $ 119,371 $ 118,819 $ 238,190 Effect of movements in exchange rates (5,664) - (5,664) End of year 113,707 118,819 232,526 Accumulated amortization and impairment Beginning of year 115,434 57,154 172,588 Amortization charge 1,181 3,868 5,049 Effect of movements in exchange rates (5,521) - (5,521) End of year 111,094 61,022 172,116 Net book value at December 31, 2019 $ 2,613 $ 57,797 $ 60,410

Long-term receivables, invest_2

Long-term receivables, investments and other (Tables)	12 Months Ended
	Dec. 31, 2020
Categories Of Noncurrent Financial Assets [Abstract]
Long-term receivables, investments and other	2020 2019 Investments in equity securities [note 26] (a) $ 43,873 $ 24,408 Derivatives [note 26] 45,605 10,504 Investment tax credits 95,642 95,474 Amounts receivable related to tax dispute [note 21] (b) 303,222 303,222 Product loan (c) 176,904 176,904 Other 5,512 26,183 670,758 636,695 Less current portion (18,716) (6,564) Net $ 652,042 $ 630,131 (a) At January 1, 2018, Cameco designated the investments shown below as equity securities at FVOCI because these equity securities represent investments that the Company intends to hold for the long term for strategic purposes . There were no dividends recognized on any of these investments during the year. (b) Cameco was required to remit or otherwise secure 50% of the cash taxes and transfer pricing penalties, plus related interest and instalment penalties assessed, in relation to its dispute with Canada Revenue Agency (CRA) (see note 21 ). In light of our vi ew of the likely outcome of the case, Cameco expects to recover the amounts remitted to CRA, including cash taxes, interest and penalties totalling $303,222,000 already paid as at December 3 1 , 2020 (December 31, 2019 - $303,222,000) (note 21 ) . (c) During 2018, as a result of the decision to temporarily suspend production at the McArthur River mine, Cameco loaned 5,400 ,000 pounds of uranium concentrate to its joint venture partner, Orano Canada Inc., (Orano). Orano is obligated to repay us in kind with uranium concentrate no later than December 31, 2023 . The loan wa s recorded at Cameco’s weighted average cost of inventory .
Equity securities designated at FVOCI	2020 2019 Investment in Denison Mines Corp. $ 20,677 $ 13,292 Investment in UEX Corporation 13,005 7,253 Investment in ISO Energy Ltd. 6,923 1,481 Investment in GoviEx 2,875 2,000 Other 393 382 $ 43,873 $ 24,408

Equity-accounted investee (Tabl

Equity-accounted investee (Tables)	12 Months Ended
	Dec. 31, 2020
Investments accounted for using equity method [Abstract]
Equity method investment summarized financial information balance sheet explanatory	The following tables summarize the financial information of JV Inkai (100%) : 2020 2019 Cash and cash equivalents $ 47,539 $ 16,699 Other current assets 115,647 139,324 Non-current assets 343,767 398,721 Current liabilities (26,397) (71,162) Non-current liabilities (39,991) (41,508) Net assets $ 440,565 $ 442,074
Equity method investment summarized financial information income statement explanatory	2020 2019 Revenue from products and services $ 252,764 $ 261,860 Cost of products and services sold (57,358) (64,199) Depreciation and amortization (24,081) (27,740) Finance income 367 651 Finance costs (825) (2,939) Other expense (12,305) (23,767) Income tax expense (44,804) (30,999) Net earnings 113,758 112,867 Other comprehensive loss (97) (1,773) Total comprehensive income $ 113,661 $ 111,094
Reconciliation of summarized financial information to carrying amount	The following table reconciles the summarized financial information to the carrying amount of Cameco’s interest in JV Inkai: 2020 2019 Opening net assets $ 442,074 $ 416,843 Total comprehensive income 113,661 111,094 Dividends declared (64,456) (66,369) Impact of foreign exchange (50,714) (19,494) Closing net assets 440,565 442,074 Cameco's share of net assets 176,226 176,830 Consolidating adjustments (a) (38,975) (30,633) Fair value increment (b) 89,184 91,697 Dividends declared but not received - 13,859 Dividends in excess of ownership percentage (c) (9,669) - Impact of foreign exchange 2,922 928 Carrying amount in the statement of financial position at December 31, 2020 $ 219,688 $ 252,681 (a) Cameco records certain consolidating adjustments to eliminate unrealized profit and amortize historical diffe rences in accounting policies. This amount is amortized to earnings over units of production. (b) Upon restructuring, Cameco assigned fair values to the assets and liabilities of JV Inkai. This increment is amortized to earnings over units of production . (c) Cameco’s share of dividends follows its production purchase entitlements which is currently hig her than its ownership interest .

Accounts payable and accrued _2

Accounts payable and accrued liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Trade And Other Current Payables [Abstract]
Schedule of payable and accrued liabilities	2020 2019 Trade payables $ 137,190 $ 100,407 Non-trade payables 58,105 66,815 Payables due to related parties [note 24] 38,354 14,577 Total $ 233,649 $ 181,799

Long-term debt (Tables)

Long-term debt (Tables)	12 Months Ended
	Dec. 31, 2020
Noncurrent Liabilities [Abstract]
Long-term debt table	2020 2019 Unsecured debentures Series E - 3.75% debentures due November 14, 2022 - 399,152 Series F - 5.09% debentures due November 14, 2042 99,319 99,302 Series G - 4.19% debentures due June 24, 2024 498,630 498,264 Series H - 2.95% debentures due October 21, 2027 397,592 - Total $ 995,541 $ 996,718 The table below represents currently scheduled maturities of long-term debt: 2021 2022 2023 2024 2025 Thereafter Total $ - - - 498,630 - 496,911 $ 995,541

Other liabilities (Tables)

Other liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Other Liabilities [Abstract]
Other liabilities	2020 2019 Deferred sales [note 17] $ 14,382 $ 17,418 Derivatives [note 26] 4,733 12,524 Accrued pension and post-retirement benefit liability [note 25] 91,729 80,737 Lease obligation 7,951 12,869 Product loan (a) 6,045 - Other 67,838 63,452 192,678 187,000 Less: current portion (26,119) (33,073) Net $ 166,559 $ 153,927 (a) The Company has standby product loan facilities with various counterparties. The arrangements allow it to borrow up to 2.0 million kgU of UF 6 conversion services and 2.6 million pounds of U 3 O 8 over the period 2020 to 2023 with repayment in kind up to D ecember 31, 2023 . Under the facilities, standby fees of up to 1 % are payable based on the market value of the facilities and interest is payable on the market value of any amounts drawn at rates ranging from 0.5 % to 2.0 %. During the year, Cameco borrowed 1 ,213,800 pounds of U 3 O 8 and 464,600 kgU of UF 6 conversion services. The U 3 O 8 loan was repaid during the year while repayment on the UF 6 loan is due no later than December 31, 2022. The loan is recorded at Cameco’s weighted average cost of inventory.

Provisions (Tables)

Provisions (Tables)	12 Months Ended
	Dec. 31, 2020
Provisions [Abstract]
Reconciliation of change of reclamation and waste provisions	Reclamation Waste disposal Total Beginning of year $ 1,050,675 $ 9,803 $ 1,060,478 Changes in estimates and discount rates [note 8] Capitalized in property, plant and equipment 127,637 - 127,637 Recognized in earnings [note 8] 23,921 (150) 23,771 Provisions used during the period (17,272) (368) (17,640) Unwinding of discount [note 19] 14,366 37 14,403 Effect of movements in exchange rates (9,727) - (9,727) End of period $ 1,189,600 $ 9,322 $ 1,198,922 Current $ 40,760 $ 1,775 $ 42,535 Non-current 1,148,840 7,547 1,156,387 $ 1,189,600 $ 9,322 $ 1,198,922
Reclamation provisions	2020 2019 Uranium $ 937,992 $ 831,352 Fuel services 251,608 219,323 Total $ 1,189,600 $ 1,050,675

Share capital (Tables)

Share capital (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Classes Of Share Capital [Abstract]
Common shares issued	Number issued (number of shares) 2020 2019 Beginning of year 395,797,732 395,792,732 Issued: Stock option plan [note 24] 465,009 5,000 End of year 396,262,741 395,797,732

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue [abstract]
Revenue - Disaggregation	Uranium Fuel services Other Total Customer geographical region Americas $ 588,827 $ 206,011 $ 7,676 $ 802,514 Europe 323,565 123,864 3,331 450,760 Asia 499,378 47,421 - 546,799 $ 1,411,770 $ 377,296 $ 11,007 $ 1,800,073 Contract type Fixed-price $ 406,021 $ 355,552 $ 7,686 $ 769,259 Market-related 1,005,749 21,744 3,321 1,030,814 $ 1,411,770 $ 377,296 $ 11,007 $ 1,800,073 Uranium Fuel services Other Total Customer geographical region Americas $ 569,535 $ 206,226 $ 59,300 $ 835,061 Europe 288,134 79,629 3,587 371,350 Asia 556,140 84,422 15,952 656,514 $ 1,413,809 $ 370,277 $ 78,839 $ 1,862,925 Contract type Fixed-price $ 349,021 $ 305,383 $ 69,703 $ 724,107 Market-related 1,064,788 64,894 9,136 1,138,818 $ 1,413,809 $ 370,277 $ 78,839 $ 1,862,925
Revenue - Contract liabilities	2020 2019 Beginning of year $ 17,418 $ 30,727 Additions 6,994 9,783 Recognized in revenue (10,026) (23,067) Effect of movements in exchange rates (4) (25) End of year $ 14,382 $ 17,418
Revenue - Remaining performance obligations	2021 2022 2023 2024 2025 Thereafter Total Uranium $ 243,069 $ 189,351 $ 179,212 $ 166,581 $ 129,450 $ 416,947 $ 1,324,610 Fuel services 319,851 272,920 212,655 215,729 216,250 677,611 1,915,016 Other 4,212 - - - - - 4,212 Total $ 567,132 $ 462,271 $ 391,867 $ 382,310 $ 345,700 $ 1,094,558 $ 3,243,838

Employee benefit expense (Table

Employee benefit expense (Tables)	12 Months Ended
	Dec. 31, 2020
Classes Of Employee Benefits Expense [Abstract]
Employee benefit expenses	2020 2019 Wages and salaries $ 226,725 $ 238,000 Statutory and company benefits 41,299 41,972 Expenses related to defined benefit plans [note 25] 5,256 4,790 Expenses related to defined contribution plans [note 25] 12,410 11,767 Equity-settled share-based compensation [note 24] 9,738 17,469 Cash-settled share-based compensation [note 24] 27,241 (1,437) Total $ 322,669 $ 312,561

Finance costs (Tables)

Finance costs (Tables)	12 Months Ended
	Dec. 31, 2020
Finance Costs [Abstract]
Schedule of finance costs	2020 2019 Interest on long-term debt $ 43,340 $ 63,136 Unwinding of discount on provisions [note 15] 14,403 20,789 Redemption of Series E debentures [note 13] 24,439 - Other charges 13,951 14,697 Total $ 96,133 $ 98,622

Other income (expense) (Tables)

Other income (expense) (Tables)	12 Months Ended
	Dec. 31, 2020
Other Income Expense [Abstract]
Other income (expense) table	2020 2019 Arbitration award (a) $ - $ 52,801 Foreign exchange gains (losses) 13,891 (18,961) Government assistance (b) 37,347 - Other 202 - Total $ 51,440 $ 33,840 (a) In the third quarter of 2019 , Cameco received an award from the tribunal of international arbitrators (Tribunal) with respect to its contract dispute with Tokyo Electric Power Company Holdings, Inc. (TEPCO). The Tribunal rejected TEPCO’s assertion that it had the right to terminate i ts uranium supply agreement and awarded damages of $ 40,300,000 (US). Damages were based on the Tribunal’s interpretation of losses under this supply agreement . (b) In response to the negative economic impact of COVID-19, the Government of Canada announced the Canada Emergency Wage Subsidy program (CEWS) . CEWS provides a subsidy on eligible remuneration based on certain criteria. During the year, the Company qualified for the subsidy for the periods April through December. There are no unfulfilled conditio ns and other contingencies attached to this government assistance. Cameco intends to apply for the CEWS in subsequent application periods, subject to continuing to meet the applicable qualification criteria.

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax [Absract]
Schedule of Deferred tax assets and liabilities	Recognized in earnings As at December 31 2020 2019 2020 2019 Assets Property, plant and equipment $ (38,389) $ 74,039 $ 280,798 $ 319,185 Provision for reclamation 28,628 2,325 222,142 193,514 Inventories 4,071 (2,163) 4,071 - Foreign exploration and development 2 (14) 5,269 5,267 Income tax losses (gains) (7,629) (108,839) 382,712 390,341 Defined benefit plan actuarial losses - - 9,410 7,947 Long-term investments and other (5,678) (17,377) 32,276 40,423 Deferred tax assets (18,995) (52,029) 936,678 956,677 Liabilities Inventories (301) 301 - 301 Deferred tax liabilities (301) 301 - 301 Net deferred tax asset (liability) $ (18,694) $ (52,330) $ 936,678 $ 956,376 Deferred tax allocated as 2020 2019 Deferred tax assets $ 936,678 $ 956,376 Deferred tax liabilities - - Net deferred tax asset $ 936,678 $ 956,376 2020 2019 Deferred tax asset at beginning of year $ 956,376 $ 1,006,012 Expense for the year in net earnings (18,694) (52,330) Recovery (expense) for the year in other comprehensive income (1,006) 2,754 Effect of movements in exchange rates 2 (60) End of year $ 936,678 $ 956,376 2020 2019 Income tax losses $ 271,163 $ 280,330 Property, plant and equipment 2,204 2,321 Provision for reclamation 75,219 75,082 Long-term investments and other 60,223 70,380 Total $ 408,809 $ 428,113
Schedule of Tax rate reconciliation	2020 2019 Earnings (loss) before income taxes and non-controlling interest $ (39,531) $ 135,018 Combined federal and provincial tax rate 26.9% 26.9% Computed income tax expense (recovery) (10,634) 36,320 Increase (decrease) in taxes resulting from: Difference between Canadian rates and rates applicable to subsidiaries in other countries 42,028 5,558 Change in unrecognized deferred tax assets (7,766) 19,646 Share-based compensation plans 398 1,146 Change in legislation (1,978) - Income in equity-accounted investee (12,155) (12,074) Change in uncertain tax positions 2,455 2,572 Other permanent differences 1,318 7,909 Income tax expense $ 13,666 $ 61,077
Schedule of Earnings and income taxes by jurisdiction	2020 2019 Earnings (loss) before income taxes Canada $ 72,809 $ 229,429 Foreign (112,340) (94,411) $ (39,531) $ 135,018 Current income taxes (recovery) Canada $ (394) $ 7,969 Foreign (4,634) 778 $ (5,028) $ 8,747 Deferred income taxes (recovery) Canada $ 9,122 $ 60,010 Foreign 9,572 (7,680) $ 18,694 $ 52,330 Income tax expense $ 13,666 $ 61,077
Schedule of Income tax losses	Date of expiry Canada US Other Total 2026 $ - $ - $ 13,819 $ 13,819 2027 - - 2,841 2,841 2030 47 - - 47 2031 - 20,436 - 20,436 2032 272 22,010 - 22,282 2033 7,037 37,520 - 44,557 2034 365,039 20,697 4,850 390,586 2035 372,376 14,401 7,752 394,529 2036 211,299 43,769 6,106 261,174 2037 143 32,785 298 33,226 2038 5,581 35,357 - 40,938 2039 6,424 27,348 - 33,772 2040 3,669 21,798 - 25,467 No expiry - - 1,115,973 1,115,973 $ 971,887 $ 276,121 $ 1,151,639 $ 2,399,647

Per share amounts (Tables)

Per share amounts (Tables)	12 Months Ended
	Dec. 31, 2020
Per Share Amounts [Abstract]
Schedule of Earnings Per Share computation per common share	2020 2019 Basic earnings (loss) per share computation Net earnings (loss) attributable to equity holders $ (53,169) $ 74,000 Weighted average common shares outstanding 395,829 395,797 Basic earnings (loss) per common share $ (0.13) $ 0.19 Diluted earnings (loss) per share computation Net earnings (loss) attributable to equity holders $ (53,169) $ 74,000 Weighted average common shares outstanding 395,829 395,797 Dilutive effect of stock options 214 258 Weighted average common shares outstanding, assuming dilution 396,043 396,055 Diluted earnings (loss) per common share $ (0.13) $ 0.19

Supplemental cash flow inform_2

Supplemental cash flow information (Tables)	12 Months Ended
	Dec. 31, 2020
Statement Of Cash Flows Disclosure [Abstract]
Statements of detailed information of cash flow	2020 2019 Changes in non-cash working capital: Accounts receivable $ 143,717 $ 58,488 Inventories (376,908) 113,388 Supplies and prepaid expenses (3,999) 3,612 Accounts payable and accrued liabilities 36,514 (53,477) Reclamation payments (17,640) (32,390) Other 25,399 6,857 Total $ (192,917) $ 96,478
Reconciliation of liabilities arising from financing activities	Long-term Interest Lease Dividends Share debt payable obligation payable capital Total Balance at January 1, 2020 $ 996,718 $ 3,030 $ 12,869 $ - $ 1,862,749 $ 2,875,366 Changes from financing cash flows: Dividends paid - - - (31,638) - (31,638) Interest paid - (65,280) (267) - - (65,547) Lease principal payments - - (3,716) - - (3,716) Shares issued, stock option plan - - - - 5,375 5,375 Repayment of long-term debt (400,000) - - - - (400,000) Proceeds of long-term debt 397,539 - - - - 397,539 Total cash changes (2,461) (65,280) (3,983) (31,638) 5,375 (97,987) Non-cash changes: Amortization of issue costs 1,284 - - - - 1,284 Dividends declared - - - 31,638 - 31,638 Interest expense - 66,228 267 - - 66,495 Right-of-use asset additions - - 2,221 - - 2,221 Right-of-use asset cancellations - - (2,165) - - (2,165) Joint operation lease obligations - - (1,361) - - (1,361) Shares issued, stock option plan - - - - 1,586 1,586 Foreign exchange - - 103 - - 103 Total non-cash changes 1,284 66,228 (935) 31,638 1,586 99,801 Balance at December 31, 2020 $ 995,541 $ 3,978 $ 7,951 $ - $ 1,869,710 $ 2,877,180

Share-based compensation plans

Share-based compensation plans (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Abstract]
Schedule of number of stock options and weighted average exercisable price	(Number of options) 2020 2019 Beginning of year 8,617,097 8,820,805 Options granted - 886,740 Options forfeited (81,991) (270,025) Options expired (1,911,558) (815,423) Options exercised [note 16] (465,009) (5,000) End of year 6,158,539 8,617,097 Exercisable 5,076,226 6,290,380 Weighted average exercise prices were as follows: 2020 2019 Beginning of year $17.44 $19.75 Options granted - 15.27 Options forfeited 22.22 22.59 Options expired 20.14 38.43 Options exercised 11.56 16.38 End of year $16.98 $17.44 Exercisable $17.73 $18.90
Total options outstanding and exercisable	Total options outstanding and exercisable at December 31, 2020 were as follows: Options outstanding Options exercisable Option price per share Number Weighted average remaining life Weighted average exercisable price Number Weighted average exercisable price $11.32 - 15.83 3,060,721 5.0 $13.72 1,978,408 $13.85 $15.84 - 26.81 3,097,818 1.8 $20.21 3,097,818 $20.21 6,158,539 5,076,226 The foregoing options have expiry dates ranging from February 28, 2021 to February 28, 2027.
Compensation expense under equity settled plans	2020 2019 Stock option plan $ 1,011 $ 4,418 Performance share unit plan (a) 2,650 7,245 Restricted share unit plan 2,903 2,679 Employee share ownership plan 3,174 3,127 Total $ 9,738 $ 17,469 (a) In the fourth quarter of 2019, the performance share unit plan was amended to allow eligible participants to elect payout of their grants in cash or shares, provided they have met their share ownership requirements. As a result, this plan is now considered cash-settled for new grants . Expenses related to PSUs granted in previous years will continue to appear as equity-settled if certain assumptions related to the calculation of fair value are met .
Expenses (recoveries) cash-settled plans	2020 2019 Deferred share unit plan $ 3,765 $ (1,001) Performance share unit plan 20,287 - Phantom stock option plan 1,340 (436) Restricted share unit plan (a) 1,849 - Total $ 27,241 $ (1,437) (a) Due to the inclusion of a new group of participants in the RSU plan that are able to elect cash settlement, grants to this group will appear as an expense of a cash-settled plan. Grants to the original group of participants are still disclosed as an expens e of an equity-settled plan .
Equity-settled plan [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Inputs measurement fair value of sharebased plans	Grant date Mar 1/20 Number of options granted 283,426 Average strike price $11.45 Expected forfeitures 13% Weighted average grant date fair values $11.45
Cash Settled Plan [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Inputs measurement fair value of sharebased plans	PSU RSU Phantom stock options Grant date Reporting date Grant date Reporting date Grant date Reporting date Mar 1/20 Dec 31/20 Mar 1/20 Dec 31/20 Mar 1/20 Dec 31/20 Number of units 636,570 1,720,636 423,180 425,176 112,140 422,291 Expected vesting 102% 129% - - - - Average strike price - - - - $11.61 $15.66 Expected dividend - - - - $0.08 $0.08 Expected volatility (a) - 22% - - 39% 41% Risk-free interest rate (a) - 0.1% - - 0.6% 0.3% Expected life of option 3.0 years 1 year 3.0 years 2.2 years 4 years 3.4 years Expected forfeitures 12% 11% 12% 12% 8% 7% Weighted average measurement date fair values $11.45 $22.01 $11.45 $17.05 $2.85 $5.43 (a) During the first quarter of 2020, the vesting conditions of the PSU plan were amended such that total shareholder return is no longer included for new grants. Due to this change, expected volatility and the risk-free interest rate will no longer be considered in calculating the fair value of new grants.

Pension and other post-retire_2

Pension and other post-retirement benefits (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Defined Benefit Plans [Abstract]
Information related to defined benefit plan	Pension benefit plans Other benefit plans 2020 2019 2020 2019 Fair value of plan assets, beginning of year $ 6,806 $ 7,177 $ - $ - Interest income on plan assets 197 262 - - Return on assets excluding interest income 130 280 - - Benefits paid (915) (912) - - Administrative costs paid (1) (1) - - Fair value of plan assets, end of year $ 6,217 $ 6,806 $ - $ - Defined benefit obligation, beginning of year $ 62,588 $ 54,271 $ 24,955 $ 21,161 Current service cost 1,977 1,586 1,010 817 Interest cost 1,673 1,807 792 841 Actuarial loss (gain) arising from: - demographic assumptions - - 102 - - financial assumptions 6,323 6,925 2,013 2,877 - experience adjustment 350 777 (2,236) 114 Benefits paid (1,765) (1,705) (809) (855) Foreign exchange 973 (1,073) - - Defined benefit obligation, end of year $ 72,119 $ 62,588 $ 25,827 $ 24,955 Defined benefit liability [note 14] $ (65,902) $ (55,782) $ (25,827) $ (24,955)
Percentages of the total fair value of assets pension plan	Pension benefit plans 2020 2019 Asset category (a) Canadian equity securities 8% 9% U.S. equity securities 12% 12% Global equity securities 8% 9% Canadian fixed income 31% 30% Other (b) 41% 40% Total 100% 100% (a) The defined benefit plan assets contain no material amounts of related p arty assets at December 31, 2020 and 2019 respectively. (b) Relates mainly to the value of the refundable tax account held by the Canada Revenue Agency. The refundable total is approximately equal to half of the sum of the realized investment income plus employer contributions less half of the benefits paid by the plan .
Components of net pension and other benefit expense	The following represents the components of net pension and other benefit expense included primarily as part of administration: Pension benefit plans Other benefit plans 2020 2019 2020 2019 Current service cost $ 1,977 $ 1,586 $ 1,010 $ 817 Net interest cost 1,476 1,545 792 841 Administration cost 1 1 - - Defined benefit expense [note 18] 3,454 3,132 1,802 1,658 Defined contribution pension expense [note 18] 12,410 11,767 - - Net pension and other benefit expense $ 15,864 $ 14,899 $ 1,802 $ 1,658
Amount of actuarial losses (gains) recognized in other comprehensive income	The total amount of actuarial losses (gains) recognized in other comprehensive income is: Pension benefit plans Other benefit plans 2020 2019 2020 2019 Actuarial loss (gain) $ 6,673 $ 7,702 $ (121) $ 2,991 Return on plan assets excluding interest income (130) (280) - - $ 6,543 $ 7,422 $ (121) $ 2,991
Defined benefit obligation and net pension and other benefit expense [Member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Assumptions to determine defined benefit obligations and expense	The assumptions used to determine the Company’s defined benefit obligation and net pension and other benefit expense were as follows at December 31 (expressed as weighted averages): Pension benefit plans Other benefit plans 2020 2019 2020 2019 Discount rate - obligation 2.4% 3.0% 2.5% 3.1% Discount rate - expense 3.0% 3.7% 3.1% 3.9% Rate of compensation increase 2.9% 3.0% - - Initial health care cost trend rate - - 5.0% 6.0% Cost trend rate declines to - - 5.0% 5.0% Year the rate reaches its final level - - 2021 2022 Dental care cost trend rate - - 4.5% 5.0%
1% Change in assumptions [member] | Defined benefit obligation and net pension and other benefit expense [Member]
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Assumptions to determine defined benefit obligations and expense	A 1% change at the reporting date to one of the relevant actuarial assumptions, holding other assumptions constant, would have affected the defined benefit obligation by the following: Pension benefit plans Other benefit plans Increase Decrease Increase Decrease Discount rate $ (9,778) $ 12,766 $ (3,270) $ 4,138 Rate of compensation increase 3,009 (2,772) n/a n/a A 1% change in any of the other assumptions would not have a significant impact on the defined benefit obligation.

Financial instruments and rel_2

Financial instruments and related risk management (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Financial Instruments [Abstract]
Pre-tax exposure to foreign currency exchange risk	Carrying value Currency (Cdn) Gain (loss) Cash and cash equivalents USD $ 86,985 $ 4,349 Accounts receivable USD 136,894 6,845 Accounts payable and accrued liabilities USD (72,576) (3,629) Net foreign currency derivatives USD 40,872 (38,811)
Counterparty credit risk, as represented by the carrying amount of the financial assets	2020 2019 Cash and cash equivalents $ 918,382 $ 1,062,431 Short-term investments 24,985 - Accounts receivable [note 6] 166,788 323,430 Derivative assets [note 10] 45,605 10,504
Exposure to credit risk for trade receivables	Carrying value Investment grade credit rating $ 160,093 Non-investment grade credit rating 5,961 Total gross carrying amount $ 166,054 Loss allowance - Net $ 166,054
Aged trade receivables	Corporate Other customers customers Total Current (not past due) $ 159,280 $ 3,649 162,929 1-30 days past due 133 434 567 More than 30 days past due 2,043 515 2,558 Total $ 161,456 $ 4,598 166,054
Liquidity risk, company's available debt facilities	The table below outlines the Company’s available debt facilities at December 31, 2020: Outstanding and Total amount committed Amount available Unsecured revolving credit facility $ 1,000,000 $ - $ 1,000,000 Letter of credit facilities [note 13] 1,698,340 1,596,488 101,852
Maturity analysis of financial liabilities	The tables below present a maturity analysis of Cameco’s financial liabilities, including principal and interest, based on the expected cash flows from the reporting date to the contractual maturity date: Due in Carrying Contractual less than Due in 1-3 Due in 3-5 Due after 5 amount cash flows 1 year years years years Accounts payable and accrued liabilities $ 233,649 $ 233,649 $ 233,649 $ - $ - $ - Long-term debt 995,541 1,000,000 - - 500,000 500,000 Foreign currency contracts 4,733 4,733 1,658 3,075 - - Lease obligation [note 14] 7,951 8,525 3,657 3,896 972 - Total contractual repayments $ 1,241,874 $ 1,246,907 $ 238,964 $ 6,971 $ 500,972 $ 500,000 Due in less than Due in 1-3 Due in 3-5 Due after 5 Total 1 year years years years Total interest payments on long-term debt $ 267,905 $ 37,840 $ 75,680 $ 44,255 $ 110,130
Carrying amounts and accounting classifications	At December 31, 2020 FVTPL Amortized cost FVOCI - designated Total Financial assets Cash and cash equivalents $ - $ 918,382 $ - $ 918,382 Short-term investments - 24,985 - 24,985 Accounts receivable [note 6] - 204,980 - 204,980 Derivative assets [note 10] Foreign currency contracts 45,605 - - 45,605 Investments in equity securities [note 10] - - 43,873 43,873 $ 45,605 $ 1,148,347 $ 43,873 $ 1,237,825 Financial liabilities Accounts payable and accrued liabilities [note 12] $ - $ 233,649 $ - $ 233,649 Lease obligation [note 14] - 7,951 - 7,951 Derivative liabilities [note 14] Foreign currency contracts 4,733 - - 4,733 Long-term debt [note 13] - 995,541 - 995,541 4,733 1,237,141 - 1,241,874 Net $ 40,872 $ (88,794) $ 43,873 $ (4,049) At December 31, 2019 FVTPL Amortized cost FVOCI - designated Total Financial assets Cash and cash equivalents $ - $ 1,062,431 $ - $ 1,062,431 Accounts receivable [note 6] - 328,044 - 328,044 Derivative assets [note 10] Foreign currency contracts 8,191 - - 8,191 Interest rate contracts 2,313 - - 2,313 Investments in equity securities [note 10] - - 24,408 24,408 $ 10,504 $ 1,390,475 $ 24,408 $ 1,425,387 Financial liabilities Accounts payable and accrued liabilities [note 12] $ - $ 181,799 $ - $ 181,799 Lease obligation - 12,869 - 12,869 Derivative liabilities [note 14] Foreign currency contracts 12,524 - - 12,524 Long-term debt [note 13] - 996,718 - 996,718 12,524 1,191,386 - 1,203,910 Net $ (2,020) $ 199,089 $ 24,408 $ 221,477
Fair value measurement, carrying amounts	As at December 31, 2020 Fair value Carrying value Level 1 Level 2 Total Derivative assets [note 10] Foreign currency contracts $ 45,605 $ - $ 45,605 $ 45,605 Investments in equity securities [note 10] 43,873 43,873 - 43,873 Derivative liabilities [note 14] Foreign currency contracts (4,733) - (4,733) (4,733) Long-term debt [note 13] (995,541) - (1,173,280) (1,173,280) Net $ (910,796) $ 43,873 $ (1,132,408) $ (1,088,535) As at December 31, 2019 Fair value Carrying value Level 1 Level 2 Total Derivative assets [note 10] Foreign currency contracts $ 8,191 $ - $ 8,191 $ 8,191 Interest rate contracts 2,313 - 2,313 2,313 Investments in equity securities [note 10] 24,408 24,408 - 24,408 Derivative liabilities [note 14] Foreign currency contracts (12,524) - (12,524) (12,524) Long-term debt [note 13] (996,718) - (1,111,923) (1,111,923) Net $ (974,330) $ 24,408 $ (1,113,943) $ (1,089,535)
Fair value of derivative instruments and classification	2020 2019 Non-hedge derivatives: Foreign currency contracts $ 40,872 $ (4,333) Interest rate contracts - 2,313 Net $ 40,872 $ (2,020) Classification: Current portion of long-term receivables, investments and other [note 10] $ 16,466 $ 4,144 Long-term receivables, investments and other [note 10] 29,139 6,360 Current portion of other liabilities [note 14] (1,658) (7,505) Other liabilities [note 14] (3,075) (5,019) Net $ 40,872 $ (2,020)
Summary of components of non-hedge derivative gains losses	The following table summarizes the different components of the gains (losses) on derivatives included in net earnings: 2020 2019 Non-hedge derivatives: Foreign currency contracts $ 30,600 $ 31,863 Interest rate contracts 5,977 2,068 Uranium contracts - (1,662) Net $ 36,577 $ 32,269

Capital management (Tables)

Capital management (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure of objectives policies and processes for managing capital abstract
Capital management	The capital structure at December 31 was as follows: 2020 2019 Long-term debt [note 13] 995,541 996,718 Cash and cash equivalents (918,382) (1,062,431) Short-term investments (24,985) - Net debt 52,174 (65,713) Non-controlling interest 206 238 Shareholders' equity 4,958,355 4,994,725 Total equity 4,958,561 4,994,963 Total capital $ 5,010,735 $ 4,929,250

Segmented information (Tables)

Segmented information (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Operating Segments [Abstract]
Business segments	A. Business segments - 2020 For the year ended December 31, 2020 Uranium Fuel services Other Total Revenue $ 1,411,770 $ 377,296 $ 11,007 $ 1,800,073 Expenses Cost of products and services sold 1,244,049 237,656 3,257 1,484,962 Depreciation and amortization 154,560 43,190 10,912 208,662 Cost of sales 1,398,609 280,846 14,169 1,693,624 Gross profit (loss) 13,161 96,450 (3,162) 106,449 Administration - - 145,344 145,344 Exploration 10,873 - - 10,873 Research and development - - 3,965 3,965 Other operating expense 23,921 - - 23,921 Loss on disposal of assets 667 405 - 1,072 Finance costs - - 96,133 96,133 Gain on derivatives - - (36,577) (36,577) Finance income - - (10,835) (10,835) Share of earnings from equity-accounted investee (36,476) - - (36,476) Other income (202) - (51,238) (51,440) Earnings (loss) before income taxes 14,378 96,045 (149,954) (39,531) Income tax expense 13,666 Net loss (53,197) Capital expenditures for the year $ 46,697 $ 30,760 $ 5 $ 77,462 For the year ended December 31, 2019 Uranium Fuel services Other Total Revenue $ 1,413,809 $ 370,277 $ 78,839 $ 1,862,925 Expenses Cost of products and services sold 1,041,922 234,423 69,206 1,345,551 Depreciation and amortization 218,832 45,856 11,061 275,749 Cost of sales 1,260,754 280,279 80,267 1,621,300 Gross profit (loss) 153,055 89,998 (1,428) 241,625 Administration - - 124,869 124,869 Exploration 13,686 - - 13,686 Research and development - - 6,058 6,058 Other operating expense 2,732 - - 2,732 Loss on disposal of assets 1,869 - - 1,869 Finance costs - - 98,622 98,622 Gain on derivatives - - (32,269) (32,269) Finance income - - (29,760) (29,760) Share of earnings from equity-accounted investee (45,360) - - (45,360) Other expense (income) (52,801) - 18,961 (33,840) Earnings (loss) before income taxes 232,929 89,998 (187,909) 135,018 Income tax expense 61,077 Net earnings 73,941 Capital expenditures for the year $ 48,092 $ 27,117 $ 2 $ 75,211
Geographic segments	Revenue is attributed to the geographic location based on the location of the entity providing the services. The Company’s revenue from external customers is as follows: 2020 2019 United States $ 1,177,756 $ 1,295,195 Canada 622,317 567,730 $ 1,800,073 $ 1,862,925 The Company’s non-current assets, excluding deferred tax assets and financial instruments, by geographic location are as follows: 2020 2019 Canada $ 3,260,144 $ 3,267,376 Australia 421,836 392,500 United States 145,328 121,102 Kazakhstan 55 80 Germany 16 24 $ 3,827,379 $ 3,781,082

Group entities (Tables)

Group entities (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Significant Investments In Subsidiaries [Abstract]
Ownership interest in subsidiaries	Principal place Ownership interest of business 2020 2019 Subsidiaries: Cameco Fuel Manufacturing Inc. Canada 100% 100% Cameco Marketing Inc. Canada 100% 100% Cameco Inc. US 100% 100% Power Resources, Inc. US 100% 100% Crow Butte Resources, Inc. US 100% 100% NUKEM, Inc. US 100% 100% Cameco Australia Pty. Ltd. Australia 100% 100% Cameco Europe Ltd. Switzerland 100% 100% Associates: JV Inkai Kazakhstan 40% 40%

Joint operations (Tables)

Joint operations (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Joint Operations [Abstract]
Joint operations proportionate interest in net assets table	Cameco reflects its proportionate interest in these assets and liabilities as follows: Principal place of business Ownership 2020 2019 Total assets McArthur River Canada 69.81% $ 1,027,617 $ 1,046,556 Key Lake Canada 83.33% 560,845 524,324 Cigar Lake Canada 50.03% 1,327,956 1,354,399 $ 2,916,418 $ 2,925,279 Total liabilities McArthur River 69.81% $ 34,597 $ 32,132 Key Lake 83.33% 278,331 227,562 Cigar Lake 50.03% 46,604 47,396 $ 359,532 $ 307,090

Related parties (Tables)

Related parties (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure of transactions between related parties [Abstract]
Compensation for key management personnel	Compensation for key management personnel was comprised of: 2020 2019 Short-term employee benefits $ 21,676 $ 21,225 Share-based compensation (a) 26,230 12,034 Post-employment benefits 6,041 5,542 Termination benefits 430 272 Total $ 54,377 $ 39,073 (a) Excludes deferred share units held by directors (see note 24).

Accounts Receivable (Details)

Accounts Receivable (Details) - CAD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Trade And Other Receivables [Abstract]
Trade receivables	$ 166,054	$ 321,638
GST/VAT receivables	38,192	4,614
Other receivables	734	1,792
Total	$ 204,980	$ 328,044

Inventories (Details)

Inventories (Details) - CAD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Operating Segments [Line Items]
Total inventory	$ 680,369,000	$ 320,770,000
Cost of sales	1,435,000,000	1,398,000,000
Uranium [Member]
Disclosure Of Operating Segments [Line Items]
Concentrate	579,653,000	204,123,000
Broken ore	45,387,000	51,094,000
Total inventory	625,040,000	255,217,000
Fuel Services [Member]
Disclosure Of Operating Segments [Line Items]
Total inventory	52,273,000	62,701,000
Other Segment [Member]
Disclosure Of Operating Segments [Line Items]
Total inventory	$ 3,056,000	$ 2,852,000

Property, plant and equipment_2

Property, plant and equipment (Details) - CAD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		$ 3,720,672
Disclosure of quantitative information about right of use assets [Abstract]
Right-of-use assets - beginning of year		8,149	$ 0
Additions		2,221	10,136
Disposals		(787)	(9)
Depreciation charge		(1,774)	(1,978)
Transfers		(1,539)
Right-of-use assets - end of year		6,270	8,149
Property, plant and equipment - End of year		3,771,557	3,720,672
Cost [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		9,013,446	9,009,461
Additions		77,462	75,211
Transfers		1,539	0
Change in reclamation provision		151,558	24,883
Disposals		(10,953)	(5,751)
Effect of movements in exchange rates		34,570	(90,358)
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		9,267,622	9,013,446
Accumulated depreciation and impairment [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		(5,300,923)	(5,127,535)
Depreciation charge		(176,821)	(236,336)
Change in reclamation provision	[1]	(23,921)	(2,732)
Disposals		9,350	3,197
Effect of movements in exchange rates		(10,020)	62,483
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		(5,502,335)	(5,300,923)
Land and buildgings [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		2,116,673
Disclosure of quantitative information about right of use assets [Abstract]
Right-of-use assets - beginning of year		2,646	0
Additions		75	3,517
Disposals		(40)	0
Depreciation charge		(875)	(871)
Transfers		0
Right-of-use assets - end of year		1,806	2,646
Property, plant and equipment - End of year		2,194,847	2,116,673
Land and buildgings [Member] | Cost [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		5,050,115	5,039,313
Additions		2,030	2,327
Transfers		37,971	17,157
Change in reclamation provision		151,558	24,883
Disposals		(1,678)	(923)
Effect of movements in exchange rates		(15,663)	(32,642)
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		5,224,333	5,050,115
Land and buildgings [Member] | Accumulated depreciation and impairment [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		(2,936,088)	(2,835,037)
Depreciation charge		(84,261)	(128,579)
Change in reclamation provision	[1]	(23,921)	(2,732)
Disposals		903	225
Effect of movements in exchange rates		12,075	30,035
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		(3,031,292)	(2,936,088)
Plant and equipment [member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		890,200
Disclosure of quantitative information about right of use assets [Abstract]
Right-of-use assets - beginning of year		5,084	0
Additions		22	5,768
Disposals		(747)	(9)
Depreciation charge		(498)	(675)
Transfers		(1,539)
Right-of-use assets - end of year		2,322	5,084
Property, plant and equipment - End of year		825,830	890,200
Plant and equipment [member] | Cost [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		2,678,165	2,654,944
Additions		7,097	7,179
Transfers		21,405	28,453
Change in reclamation provision		0	0
Disposals		(3,385)	(3,486)
Effect of movements in exchange rates		(3,438)	(8,925)
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		2,699,844	2,678,165
Plant and equipment [member] | Accumulated depreciation and impairment [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		(1,793,049)	(1,697,178)
Depreciation charge		(89,550)	(105,700)
Change in reclamation provision		0	0
Disposals		2,997	2,194
Effect of movements in exchange rates		3,266	7,635
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		(1,876,336)	(1,793,049)
Furniture and fixtures [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		4,687
Disclosure of quantitative information about right of use assets [Abstract]
Right-of-use assets - beginning of year		419	0
Additions		2,124	851
Disposals		0	0
Depreciation charge		(401)	(432)
Transfers		0
Right-of-use assets - end of year		2,142	419
Property, plant and equipment - End of year		6,807	4,687
Furniture and fixtures [Member] | Cost [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		80,869	80,083
Additions		855	158
Transfers		2,554	951
Change in reclamation provision		0	0
Disposals		(5,299)	(142)
Effect of movements in exchange rates		(68)	(181)
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		78,911	80,869
Furniture and fixtures [Member] | Accumulated depreciation and impairment [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		(76,601)	(74,860)
Depreciation charge		(3,010)	(2,057)
Change in reclamation provision		0	0
Disposals		5,299	139
Effect of movements in exchange rates		66	177
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		(74,246)	(76,601)
Under constructions [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		95,658
Disclosure of quantitative information about right of use assets [Abstract]
Right-of-use assets - beginning of year		0	0
Right-of-use assets - end of year		0	0
Property, plant and equipment - End of year		102,253	95,658
Under constructions [Member] | Cost [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		132,457	114,060
Additions		67,477	65,482
Transfers		(60,391)	(46,561)
Change in reclamation provision		0	0
Disposals		(492)	(507)
Effect of movements in exchange rates		0	(17)
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		139,051	132,457
Under constructions [Member] | Accumulated depreciation and impairment [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		(36,799)	(36,799)
Depreciation charge		0	0
Change in reclamation provision		0	0
Disposals		1	0
Effect of movements in exchange rates		0	0
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		(36,798)	(36,799)
Exploration and evaluation [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		613,454
Disclosure of quantitative information about right of use assets [Abstract]
Right-of-use assets - beginning of year		0	0
Right-of-use assets - end of year		0	0
Property, plant and equipment - End of year		641,820	613,454
Exploration and evaluation [Member] | Cost [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		1,071,840	1,121,061
Additions		3	65
Transfers		0	0
Change in reclamation provision		0	0
Disposals		(99)	(693)
Effect of movements in exchange rates		53,739	(48,593)
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		1,125,483	1,071,840
Exploration and evaluation [Member] | Accumulated depreciation and impairment [Member]
Disclosure Of Property Plant And Equipment [Line Items]
Property, plant and equipment - Beginning of year		(458,386)	(483,661)
Depreciation charge		0	0
Change in reclamation provision		0	0
Disposals		150	639
Effect of movements in exchange rates		(25,427)	24,636
Disclosure of quantitative information about right of use assets [Abstract]
Property, plant and equipment - End of year		$ (483,663)	$ (458,386)
[1]	Asset retirement obligation assets are adjusted when the Company updates its reclamatio n provisions due to new cash flow estimates or changes in discount and inflation rates. When the assets of an operation have been written off due to an impairment, as is the case with our Rabbit Lake operation and some of our operations in the United States , the adjustment is recorded directly to the statement of earnings as other operating expense or income .

Property, plant and equipment_3

Property, plant and equipment (Narrative) (Details)	Dec. 31, 2020CAD ($)
Disclosure Of Property Plant And Equipment [Line Items]
Contracutal capital commitments	$ 47,000,000

Intangible assets (Details)

Intangible assets (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of carrying amount [Line Items]
Intangible assets, beginning of year	$ 60,410
Intangible assets, end of year	55,822	$ 60,410
Cost [Member]
Reconciliation of carrying amount [Line Items]
Intangible assets, beginning of year	232,526	238,190
Effect of movements in exchange rates	(2,319)	(5,664)
Intangible assets, end of year	230,207	232,526
Accumulated amortization [member]
Reconciliation of carrying amount [Line Items]
Intangible assets, beginning of year	(172,116)	(172,588)
Amortization charge	(4,708)	(5,049)
Effect of movements in exchange rates	2,439	5,521
Intangible assets, end of year	(174,385)	(172,116)
Contracts [member]
Reconciliation of carrying amount [Line Items]
Intangible assets, beginning of year	2,613
Intangible assets, end of year	1,725	2,613
Contracts [member] | Cost [Member]
Reconciliation of carrying amount [Line Items]
Intangible assets, beginning of year	113,707	119,371
Effect of movements in exchange rates	(2,319)	(5,664)
Intangible assets, end of year	111,388	113,707
Contracts [member] | Accumulated amortization [member]
Reconciliation of carrying amount [Line Items]
Intangible assets, beginning of year	(111,094)	(115,434)
Amortization charge	(1,008)	(1,181)
Effect of movements in exchange rates	2,439	5,521
Intangible assets, end of year	(109,663)	(111,094)
Intellectual Property [member]
Reconciliation of carrying amount [Line Items]
Intangible assets, beginning of year	57,797
Intangible assets, end of year	54,097	57,797
Intellectual Property [member] | Cost [Member]
Reconciliation of carrying amount [Line Items]
Intangible assets, beginning of year	118,819	118,819
Effect of movements in exchange rates	0	0
Intangible assets, end of year	118,819	118,819
Intellectual Property [member] | Accumulated amortization [member]
Reconciliation of carrying amount [Line Items]
Intangible assets, beginning of year	(61,022)	(57,154)
Amortization charge	(3,700)	(3,868)
Effect of movements in exchange rates	0	0
Intangible assets, end of year	$ (64,722)	$ (61,022)

Long-term receivables, invest_3

Long-term receivables, investments and other (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2020CAD ($)lb	Dec. 31, 2019CAD ($)
Categories Of Noncurrent Financial Assets [Abstract]
Investments in equity securities	[1]	$ 43,873	$ 24,408
Derivatives		45,605	10,504
Investment tax credits		95,642	95,474
Amounts receivable related to tax dispute	[2]	303,222	303,222
Product loan	[3]	176,904	176,904
Other		5,512	26,183
Total (current and non current portion)		670,758	636,695
Less current portion		(18,716)	(6,564)
Net		$ 652,042	$ 630,131
Uranium [Member]
Disclosure of products and services [line items]
Product loan maturity		December 31, 2023
Product loan quantity | lb		5,400,000
[1]	At January 1, 2018, Cameco designated the investments shown below as equity securities at FVOCI because these equity securities represent investments that the Company intends to hold for the long term for strategic purposes . There were no dividends recognized on any of these investments during the year.
[2]	Cameco was required to remit or otherwise secure 50% of the cash taxes and transfer pricing penalties, plus related interest and instalment penalties assessed, in relation to its dispute with Canada Revenue Agency (CRA) (see note 21 ). In light of our vi ew of the likely outcome of the case, Cameco expects to recover the amounts remitted to CRA, including cash taxes, interest and penalties totalling $303,222,000 already paid as at December 3 1 , 2020 (December 31, 2019 - $303,222,000) (note 21 ) .
[3]	During 2018, as a result of the decision to temporarily suspend production at the McArthur River mine, Cameco loaned 5,400 ,000 pounds of uranium concentrate to its joint venture partner, Orano Canada Inc., (Orano). Orano is obligated to repay us in kind with uranium concentrate no later than December 31, 2023 . The loan wa s recorded at Cameco’s weighted average cost of inventory .

Long-term receivables, invest_4

Long-term receivables, investments and other - Equity investments (Details) - CAD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Disclosure of FV of investments in equity instruments designated as measured at FVOCI
Investments in equity securities	[1]	$ 43,873	$ 24,408
Denison [Member]
Disclosure of FV of investments in equity instruments designated as measured at FVOCI
Investments in equity securities		20,677	13,292
UEX [Member]
Disclosure of FV of investments in equity instruments designated as measured at FVOCI
Investments in equity securities		13,005	7,253
GoviEx [Member]
Disclosure of FV of investments in equity instruments designated as measured at FVOCI
Investments in equity securities		2,875	2,000
ISO Energy [Member]
Disclosure of FV of investments in equity instruments designated as measured at FVOCI
Investments in equity securities		6,923	1,481
Other [Member]
Disclosure of FV of investments in equity instruments designated as measured at FVOCI
Investments in equity securities		$ 393	$ 382
[1]	At January 1, 2018, Cameco designated the investments shown below as equity securities at FVOCI because these equity securities represent investments that the Company intends to hold for the long term for strategic purposes . There were no dividends recognized on any of these investments during the year.

Equity-accounted investee - Ass

Equity-accounted investee - Associate financial position (Details) - CAD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of significant investments in associates [Line Items]
Cash and cash equivalents	$ 918,382	$ 1,062,431	$ 711,528
Non-current assets	5,635,787	5,620,270
Current liabilities	(303,783)	(277,410)
Non-current liabilities	(2,318,487)	(2,154,875)
JV Inkai [Member]
Disclosure of significant investments in associates [Line Items]
Cash and cash equivalents	47,539	16,699
Other current assets	115,647	139,324
Non-current assets	343,767	398,721
Current liabilities	(26,397)	(71,162)
Non-current liabilities	(39,991)	(41,508)
Net assets	$ 440,565	$ 442,074	$ 416,843

Equity-accounted investee - A_2

Equity-accounted investee - Associate statement of earnings (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of significant investments in associates [Line Items]
Revenue from products and services	$ 1,800,073	$ 1,862,925
Cost of products and services sold	(1,484,962)	(1,345,551)
Depreciation and amortization	(208,662)	(275,749)
Finance income	10,835	29,760
Finance costs	(96,133)	(98,622)
Income tax expense	(13,666)	(61,077)
Net earnings (loss)	(53,197)	73,941
Other comprehensive income (loss)	38,795	(40,753)
Total comprehensive income (loss)	(14,402)	33,188
JV Inkai [Member]
Disclosure of significant investments in associates [Line Items]
Revenue from products and services	252,764	261,860
Cost of products and services sold	(57,358)	(64,199)
Depreciation and amortization	(24,081)	(27,740)
Finance income	367	651
Finance costs	(825)	(2,939)
Other expense	(12,305)	(23,767)
Income tax expense	(44,804)	(30,999)
Net earnings (loss)	113,758	112,867
Other comprehensive income (loss)	(97)	(1,773)
Total comprehensive income (loss)	$ 113,661	$ 111,094

Equity-accounted investee - Rec

Equity-accounted investee - Reconciliation of carrying amount (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020		Dec. 31, 2019
Disclosure of significant investments in associates [Line Items]
Total comprehensive income	$ (14,402)		$ 33,188
Investment in equity-accounted investee	219,688		252,681
JV Inkai Associate [Member]
Disclosure of significant investments in associates [Line Items]
Opening net assets	442,074		416,843
Total comprehensive income	113,661		111,094
Dividends declared	(64,456)		(66,369)
Impact of foreign exchange	(50,714)		(19,494)
Closing net assets	440,565		442,074
Cameco's share of net assets	176,226		176,830
Consolidating adjustments	(38,975)	[1]	(30,633)
Fair value increment	89,184	[2]	91,697
Dividends declared but not yet received	0		13,859
Dividends in excess of ownership percentage	(9,669)	[3]	0
Impact of foreign exchange	2,922		928
Investment in equity-accounted investee	$ 219,688		$ 252,681
[1]	Cameco records certain consolidating adjustments to eliminate unrealized profit and amortize historical diffe rences in accounting policies. This amount is amortized to earnings over units of production.
[2]	Upon restructuring, Cameco assigned fair values to the assets and liabilities of JV Inkai. This increment is amortized to earnings over units of production .
[3]	Cameco’s share of dividends follows its production purchase entitlements which is currently hig her than its ownership interest .

Accounts payable and accrued _3

Accounts payable and accrued liabilities (Details) - CAD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Trade And Other Current Payables [Abstract]
Trade payables	$ 137,190	$ 100,407
Non-trade payables	58,105	66,815
Payables due to related parties	38,354	14,577
Total	$ 233,649	$ 181,799

Long term debt - Schedules (Det

Long term debt - Schedules (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Oct. 21, 2020	Dec. 31, 2019
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	$ 995,541		$ 996,718
Long-term debt	995,541		996,718
2021 [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	0
2022 [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	0
2023 [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	0
2024 [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	498,630
2025 [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	0
Thereafter [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	496,911
Series E [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	$ 0		399,152
Stated interest rates on debentures	3.75%
Maturity date of borrowings	November 14, 2022
Series F [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	$ 99,319		99,302
Stated interest rates on debentures	5.09%
Maturity date of borrowings	November 14, 2042
Series G [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	$ 498,630		498,264
Stated interest rates on debentures	4.19%
Maturity date of borrowings	June 24, 2024
Series H [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures	$ 397,592		$ 0
Stated interest rates on debentures	2.95%	2.95%
Maturity date of borrowings	October 21, 2027

Long term debt - Schedules (Nar

Long term debt - Schedules (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020CAD ($)	Dec. 31, 2019CAD ($)	Nov. 20, 2020CAD ($)	Oct. 21, 2020CAD ($)
Disclosure of detailed information about borrowings [line items]
Proceeds of long-term debt	$ 397,539,000	$ 0
Redemption of Series E debentures	24,439,000	0
Revolving Credit Facilities [Abstract]
Gross Unsecured Revolving Credit Facility Available	1,000,000,000
Maximum Letters of credit under the facility	100,000,000
Increase in revolving credit facility with minimum Increments	50,000,000
Maximum unsecured revolving credit facility	1,250,000,000
Unsecured loans received	0
Outstanding letters of credit facility	1,596,488,000	1,528,603,000
Gross Letters Of Credit Committments	$ 1,698,340,000	$ 1,719,120,000
Debt to tangible net worth ratio	1
Credit Facility Maturity	November 1, 2023
Series E [Member]
Disclosure of detailed information about borrowings [line items]
Stated interest rates on debentures	3.75%
Unsecured debentures redeemed, principal amount			$ 400,000,000
Redemption of Series E debentures	$ 24,439,000
Series H [Member]
Disclosure of detailed information about borrowings [line items]
Unsecured debentures issued, principal amount				$ 400,000,000
Stated interest rates on debentures	2.95%			2.95%
Proceeds of long-term debt	$ 397,500,000
Effective interest rate				3.05%

Other liabilities (Details)

Other liabilities (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Other Liabilities [Abstract]
Deferred sales	$ 14,382	$ 17,418
Derivatives	4,733	12,524
Accrued pension and post-retirement benefit liability	91,729	80,737
Lease obligation	7,951	12,869
Product loan	6,045	0
Other	67,838	63,452
Total other liabilities	192,678	187,000
Less current portion	(26,119)	(33,073)
Net	$ 166,559	$ 153,927
Disclosure of quantitative information about leases for lessee [Abstract]
Short-term leases	Expenses related to short-term leases and leases of low-value assets were insignificant during 2020.
Low-value leases	Expenses related to short-term leases and leases of low-value assets were insignificant during 2020.

Other liabilities (Narrative) (

Other liabilities (Narrative) (Details) - Product Loan [Member]	12 Months Ended
	Dec. 31, 2020lbkg
Range [member]
Disclosure of detailed information about product loans [line items]
Product loan maturity	December 31, 2023
Bottom of range [member]
Disclosure of detailed information about product loans [line items]
Interest rate	0.50%
Top of range [member]
Disclosure of detailed information about product loans [line items]
Standby interest rate	1.00%
Interest rate	2.00%
Uranium [Member] | Range [member]
Disclosure of detailed information about product loans [line items]
Product loans received | lb	1,213,800
Uranium [Member] | Top of range [member]
Disclosure of detailed information about product loans [line items]
Available quantity | lb	2,600,000
UF6 [Member] | Range [member]
Disclosure of detailed information about product loans [line items]
Product loans received | kg	464,600
UF6 [Member] | Top of range [member]
Disclosure of detailed information about product loans [line items]
Available quantity | kg	2,000,000

Provisions (Details)

Provisions (Details) - CAD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Provisions [Line Items]
Beginning of year	$ 1,060,478,000
Changes in estimates and discont rates [Abstract]
Capitalized in property, plant and equipment	127,637,000
Recognized in earnings	23,771,000
Provisions used during the period	(17,640,000)
Unwinding of discount	14,403,000
Effect of movements in exchange rates	(9,727,000)
End of period	1,198,922,000
Current	42,535,000	$ 56,248,000
Non-current	1,156,387,000	1,004,230,000
Outstanding letters of credit facility	1,596,488,000	1,528,603,000
Reclamation [Member]
Provisions [Line Items]
Beginning of year	1,050,675,000
Changes in estimates and discont rates [Abstract]
Capitalized in property, plant and equipment	127,637,000
Recognized in earnings	23,921,000
Provisions used during the period	(17,272,000)
Unwinding of discount	14,366,000
Effect of movements in exchange rates	(9,727,000)
End of period	1,189,600,000
Current	40,760,000
Non-current	1,148,840,000
Estimated total future decommissioning and reclamation costs	$ 1,130,495,000	1,127,487,000
Description of period, majority of expenditures will occur after	2026
Outstanding letters of credit facility	$ 1,021,142,000	994,129,000
Reclamation [Member] | Uranium [Member]
Provisions [Line Items]
Beginning of year	831,352,000
Changes in estimates and discont rates [Abstract]
End of period	937,992,000
Reclamation [Member] | Fuel Services [Member]
Provisions [Line Items]
Beginning of year	219,323,000
Changes in estimates and discont rates [Abstract]
End of period	251,608,000
Waste Disposal [Member]
Provisions [Line Items]
Beginning of year	9,803,000
Changes in estimates and discont rates [Abstract]
Capitalized in property, plant and equipment	0
Recognized in earnings	(150,000)
Provisions used during the period	(368,000)
Unwinding of discount	37,000
Effect of movements in exchange rates	0
End of period	9,322,000
Current	1,775,000
Non-current	7,547,000
Waste Disposal [Member] | Fuel Services [Member]
Changes in estimates and discont rates [Abstract]
Estimated total future decommissioning and reclamation costs	$ 8,044,000	$ 8,451,000

Share Capital (Details)

Share Capital (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of issued shares [Line Items]
Beginning of year	395,797,732	395,792,732
Stock option plan	465,009	5,000
End of year	396,262,741	395,797,732
Common shares [member]
Number of issued shares [Line Items]
Common shares par value	no
Class B share preferences	no shareholder, resident in Canada, is allowed to own more than 25% of the Company’s outstanding common shares, either individually or together with associates. A non-resident of Canada is not allowed to own more than 15%. In addition, no more than 25% of total shareholder votes cast may be cast by non-resident shareholders.
Dividends Paid Ordinary Shares Per Share	$ 0.08	$ 0.08
Common shares [member] | Share Holder Resident [Member] | Maximum [member]
Number of issued shares [Line Items]
Ownership in Cameco	25.00%	25.00%
Common shares [member] | Share Holder Non-Resident [Member] | Maximum [member]
Number of issued shares [Line Items]
Ownership in Cameco	15.00%	15.00%
Percentage Votes Of Ordinary Shares Of Company	25.00%	25.00%
Class B Shares [Member]
Number of issued shares [Line Items]
Class B share par value	$ 1
Class B share preferences	entitles the shareholder to vote separately as a class in respect of any proposal to locate the head office of Cameco to a place not in the province of Saskatchewan

Revenue - Disaggregation (Detai

Revenue - Disaggregation (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reportable Segments Member
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	$ 1,800,073	$ 1,862,925
Uranium [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	1,411,770	1,413,809
Fuel Services [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	377,296	370,277
Other Segment [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	11,007	78,839
Fixed price Contracts Member | Reportable Segments Member
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	769,259	724,107
Fixed price Contracts Member | Uranium [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	406,021	349,021
Fixed price Contracts Member | Fuel Services [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	355,552	305,383
Fixed price Contracts Member | Other Segment [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	7,686	69,703
Market Price Contracts Member [Member] | Reportable Segments Member
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	1,030,814	1,138,818
Market Price Contracts Member [Member] | Uranium [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	1,005,749	1,064,788
Market Price Contracts Member [Member] | Fuel Services [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	21,744	64,894
Market Price Contracts Member [Member] | Other Segment [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	3,321	9,136
Americas [Member] | Reportable Segments Member
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	802,514	835,061
Americas [Member] | Uranium [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	588,827	569,535
Americas [Member] | Fuel Services [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	206,011	206,226
Americas [Member] | Other Segment [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	7,676	59,300
Europe [Member] | Reportable Segments Member
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	450,760	371,350
Europe [Member] | Uranium [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	323,565	288,134
Europe [Member] | Fuel Services [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	123,864	79,629
Europe [Member] | Other Segment [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	3,331	3,587
Asia [Member] | Reportable Segments Member
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	546,799	656,514
Asia [Member] | Uranium [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	499,378	556,140
Asia [Member] | Fuel Services [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	47,421	84,422
Asia [Member] | Other Segment [Member]
Disclosure Of Disaggregation Of Revenue From Contracts With Customers [line items]
Revenue From Contracts With Customers	$ 0	$ 15,952

Revenue - Deferred revenue (Det

Revenue - Deferred revenue (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Contract Liabilities Abstract
Beginning of year	$ 17,418	$ 30,727
Additions	6,994	9,783
Recognized in revenue	(10,026)	(23,067)
Effect of movements in exchange rates	(4)	(25)
End of year	$ 14,382	$ 17,418

Revenue - Future sales commitme

Revenue - Future sales commitments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020CAD ($)
Reportable Segments Member
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	$ 3,243,838
USD/CAD average foreign exchange rate	1.3
Reportable Segments Member | 2021 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	$ 567,132
Reportable Segments Member | 2022 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	462,271
Reportable Segments Member | 2023 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	391,867
Reportable Segments Member | 2024 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	382,310
Reportable Segments Member | 2025 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	345,700
Reportable Segments Member | Thereafter [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	1,094,558
Uranium [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	1,324,610
Uranium [Member] | 2021 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	243,069
Uranium [Member] | 2022 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	189,351
Uranium [Member] | 2023 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	179,212
Uranium [Member] | 2024 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	166,581
Uranium [Member] | 2025 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	129,450
Uranium [Member] | Thereafter [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	416,947
Fuel Services [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	1,915,016
Fuel Services [Member] | 2021 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	319,851
Fuel Services [Member] | 2022 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	272,920
Fuel Services [Member] | 2023 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	212,655
Fuel Services [Member] | 2024 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	215,729
Fuel Services [Member] | 2025 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	216,250
Fuel Services [Member] | Thereafter [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	677,611
Other Segment [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	4,212
Other Segment [Member] | 2021 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	4,212
Other Segment [Member] | 2022 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	0
Other Segment [Member] | 2023 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	0
Other Segment [Member] | 2024 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	0
Other Segment [Member] | 2025 [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	0
Other Segment [Member] | Thereafter [Member]
Disclosure of transaction price allocated to remaining performance obligations [Line Items]
Transaction Price Allocated To Remaining Performance Obligations	$ 0

Revenue - Narrative (Details)

Revenue - Narrative (Details) - CAD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue [abstract]
Revenue From Performance Obligations Satisfied Or Partially Satisfied In Previous Periods		$ 78,000
Explanation Of Effect That Timing Of Satisfaction Of Performance Obligations And Typical Timing Of Payment Have On Contract Assets And Contract Liabilities Explanatory	The revenue related to the fuel fabricati on services and storage is recognized over time while the revenue related to future conversion deliveries is expected to be recognized between 20 21 and 20 27.
Statement That Practical Expedient About Incremental Costs Of Obtaining Contract Has Been Used	Cameco expenses the incremental costs of obtaining a contract as incurred as the amortization period is less than a year.
Disclosure Of Information About Methods Inputs And Assumptions Used For Determining Transaction Price Explanatory	Cam eco’s sales portfolio consists of sho rt and long-term sales commitments. The contracts can be executed well in advance of a delivery and include both fixed and market-related pricing.
ExplanationOfWhetherAnyConsiderationFromContractsWithCustomersIsNotIncludedInDisclosureOfTransactionPriceAllocatedToRemainingPerformanceObligations	Cameco’s total revenue that will be earned will also include revenue from contracts with market-related pricing. The Company has elected to exclude these amounts from the table as the transaction price will not be known until the time of delivery.
Reduction Of Revenue From Performance Obligation	$ 268,000

Employee benefit expense (Detai

Employee benefit expense (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Classes Of Employee Benefits Expense [Abstract]
Wages and salaries	$ 226,725	$ 238,000
Statutory and company benefits	41,299	41,972
Expenses related to defined benefit plans	5,256	4,790
Expenses related to defined contribution plans	12,410	11,767
Equity-settled share-based compensation	9,738	17,469
Cash-settled share-based compensation	27,241	(1,437)
Employee benefit expense	$ 322,669	$ 312,561

Finance cost (Details)

Finance cost (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Borrowing costs [abstract]
Interest on long-term debt	$ 43,340	$ 63,136
Unwinding of discount on provisions	14,403	20,789
Redemption of Series E debentures	24,439	0
Other charges	13,951	14,697
Finance costs	96,133	$ 98,622
Borrowing costs capitalised	$ 0

Other income (expense) (Details

Other income (expense) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020CAD ($)		Dec. 31, 2019CAD ($)	Dec. 31, 2019USD ($)	[1]
Other Income Expense [Abstract]
Arbitration award	$ 0	[1]	$ 52,801	$ 40,300,000
Foreign exchange gains (losses)	13,891		(18,961)
Government assistance	37,347	[2]	0
Other	202		0
Total other income (expense)	$ 51,440		$ 33,840
[1]	In the third quarter of 2019 , Cameco received an award from the tribunal of international arbitrators (Tribunal) with respect to its contract dispute with Tokyo Electric Power Company Holdings, Inc. (TEPCO). The Tribunal rejected TEPCO’s assertion that it had the right to terminate i ts uranium supply agreement and awarded damages of $ 40,300,000 (US). Damages were based on the Tribunal’s interpretation of losses under this supply agreement .
[2]	In response to the negative economic impact of COVID-19, the Government of Canada announced the Canada Emergency Wage Subsidy program (CEWS) . CEWS provides a subsidy on eligible remuneration based on certain criteria. During the year, the Company qualified for the subsidy for the periods April through December. There are no unfulfilled conditio ns and other contingencies attached to this government assistance. Cameco intends to apply for the CEWS in subsequent application periods, subject to continuing to meet the applicable qualification criteria.

Income Taxes - Significant comp

Income Taxes - Significant components of deferred tax assets and liabilities (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	$ (18,694)	$ (52,330)
Deferred tax assets	936,678	956,376
Deferred tax liabilities	0	0
Net deferred tax asset	936,678	956,376	$ 1,006,012
Property, plant and equipment [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	(38,389)	74,039
Net deferred tax assets	280,798	319,185
Provision for reclamation [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	28,628	2,325
Net deferred tax assets	222,142	193,514
Inventories [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	4,071	(2,163)
Net deferred tax assets	4,071	0
Net deferred tax liabilities	0	301
Foreign exploration and development [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	2	(14)
Net deferred tax assets	5,269	5,267
Income tax losses (gains) [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	(7,629)	(108,839)
Net deferred tax assets	382,712	390,341
Defined benefit plan actuarial losses [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	0	0
Net deferred tax assets	9,410	7,947
Long-term investments and other, deferred tax assets [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	(5,678)	(17,377)
Net deferred tax assets	32,276	40,423
Deferred tax assets [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	(18,995)	(52,029)
Net deferred tax assets	936,678	956,677
Inventories [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	(301)	301
Deferred tax liabilities [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Net deferred tax asset, recognized in earnings	(301)	301
Net deferred tax liabilities	$ 0	$ 301

Income Taxes - Movement in net

Income Taxes - Movement in net deferred tax assets and liabilities (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of changes in deferred tax liability (asset) [abstract]
Net deferred tax asset, beginning of year	$ 956,376	$ 1,006,012
Recovery (expense) for the year in net earnings	(18,694)	(52,330)
Recovery (expense) for the year in other comprehensive income	(1,006)	2,754
Effect of movements in exchange rates	2	(60)
Net deferred tax asset, end of year	$ 936,678	$ 956,376

Income Taxes - Significant co_2

Income Taxes - Significant components of unrecognized deferred tax assets (Details) - CAD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unrecognized deferred tax assets	$ 408,809	$ 428,113
Income tax losses (gains) [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unrecognized deferred tax assets	271,163	280,330
Property, plant and equipment, deferred tax assets [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unrecognized deferred tax assets	2,204	2,321
Provision for reclamation [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unrecognized deferred tax assets	75,219	75,082
Long-term investments and other, deferred tax assets [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unrecognized deferred tax assets	$ 60,223	$ 70,380

Income Taxes - Tax rate reconci

Income Taxes - Tax rate reconciliation (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Reconciliation Of Accounting Profit Multiplied By Applicable Tax Rates [Abstract]
Earnings (loss) before income taxes and non-controlling interest	$ (39,531)	$ 135,018
Combined federal and provincial tax rate	26.90%	26.90%
Computed income tax expense (recovery)	$ (10,634)	$ 36,320
Increase Decrease In Taxes Abstract
Difference between Canadian rates and rates applicable to subsidiaries in other countries	42,028	5,558
Change in unrecognized deferred tax assets	(7,766)	19,646
Share-based compensation plans	398	1,146
Income in equity-accounted investee	(12,155)	(12,074)
Change in legislation	(1,978)	0
Change in uncertain tax positions	2,455	2,572
Other permanent differences	1,318	7,909
Income tax expense (recovery)	$ 13,666	$ 61,077

Income Taxes - Earnings and inc

Income Taxes - Earnings and income taxes by jurisdiction (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of geographical areas [line items]
Earnings (loss) before income taxes	$ (39,531)	$ 135,018
Current income taxes	(5,028)	8,747
Deferred income taxes (recovery)	18,694	52,330
Income tax expense (recovery)	13,666	61,077
Canada [member]
Disclosure of geographical areas [line items]
Earnings (loss) before income taxes	72,809	229,429
Current income taxes	(394)	7,969
Deferred income taxes (recovery)	9,122	60,010
Foreign [member]
Disclosure of geographical areas [line items]
Earnings (loss) before income taxes	(112,340)	(94,411)
Current income taxes	(4,634)	778
Deferred income taxes (recovery)	$ 9,572	$ (7,680)

Income Taxes - Income tax losse

Income Taxes - Income tax losses carried forward (Details) - CAD ($)	Dec. 31, 2020	Dec. 31, 2019
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unrecognized deferred tax assets	$ 1,013,730,000	$ 1,048,264,000
Unused tax loss carry forward	2,399,647,000
Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	971,887,000
US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	276,121,000
Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	1,151,639,000
Unused tax expiry 2026 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	13,819,000
Unused tax expiry 2026 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2026 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2026 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	13,819,000
Unused tax expiry 2027 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	2,841,000
Unused tax expiry 2027 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2027 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2027 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	2,841,000
Unused tax expiry 2030 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	47,000
Unused tax expiry 2030 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	47,000
Unused tax expiry 2030 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2030 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2031 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	20,436,000
Unused tax expiry 2031 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2031 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	20,436,000
Unused tax expiry 2031 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2032 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	22,282,000
Unused tax expiry 2032 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	272,000
Unused tax expiry 2032 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	22,010,000
Unused tax expiry 2032 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2033 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	44,557,000
Unused tax expiry 2033 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	7,037,000
Unused tax expiry 2033 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	37,520,000
Unused tax expiry 2033 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2034 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	390,586,000
Unused tax expiry 2034 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	365,039,000
Unused tax expiry 2034 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	20,697,000
Unused tax expiry 2034 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	4,850,000
Unused tax expiry 2035 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	394,529,000
Unused tax expiry 2035 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	372,376,000
Unused tax expiry 2035 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	14,401,000
Unused tax expiry 2035 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	7,752,000
Unused tax expiry 2036 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	261,174,000
Unused tax expiry 2036 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	211,299,000
Unused tax expiry 2036 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	43,769,000
Unused tax expiry 2036 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	6,106,000
Unused tax expiry 2037 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	33,226,000
Unused tax expiry 2037 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	143,000
Unused tax expiry 2037 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	32,785,000
Unused tax expiry 2037 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	298,000
Unused tax expiry 2038 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	40,938,000
Unused tax expiry 2038 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	5,581,000
Unused tax expiry 2038 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	35,357,000
Unused tax expiry 2038 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2039 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	33,772,000
Unused tax expiry 2039 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	6,424,000
Unused tax expiry 2039 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	27,348,000
Unused tax expiry 2039 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry 2040 [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	25,467,000
Unused tax expiry 2040 [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	3,669,000
Unused tax expiry 2040 [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	21,798,000
Unused tax expiry 2040 [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry no expiry [Member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	1,115,973,000
Unused tax expiry no expiry [Member] | Canada [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry no expiry [Member] | US [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	0
Unused tax expiry no expiry [Member] | Other [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Unused tax loss carry forward	$ 1,115,973,000

Income Taxes - Narratives (Deta

Income Taxes - Narratives (Details) - CAD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Provisions [Line Items]
Corresponding increase in tax expense	$ (5,028,000)	$ 8,747,000
Letters of credit oustanding	1,596,488,000	$ 1,528,603,000
Canadian Revenue Agency [member]
Provisions [Line Items]
Amount of potential taxable income consequences from tax dispute	$ 6,600,000,000
Percentage of taxes and interest charges	50.00%
Penalties related to transfer pricing [member] | Canadian Revenue Agency [member]
Provisions [Line Items]
Provision for CRA transfer price dispute	$ 371,000,000
Provision for uncertain tax positions [member] | Canadian Revenue Agency [member]
Provisions [Line Items]
Corresponding increase in tax expense	2,600,000,000
Provision for uncertain tax positions [member] | Canadian Revenue Agency [member] | Bottom of range [member]
Provisions [Line Items]
Amount of potential taxable income consequences from tax dispute	6,600,000,000
Provision for uncertain tax positions [member] | Canadian Revenue Agency [member] | Top of range [member]
Provisions [Line Items]
Amount of potential taxable income consequences from tax dispute	8,700,000,000
Provision for uncertain tax positions [member] | Penalties related to cash taxes and transfer pricing [member] | Canadian Revenue Agency [member] | Bottom of range [member]
Provisions [Line Items]
Provision for CRA transfer price dispute	1,950,000,000
Provision for uncertain tax positions [member] | Penalties related to cash taxes and transfer pricing [member] | Canadian Revenue Agency [member] | Top of range [member]
Provisions [Line Items]
Provision for CRA transfer price dispute	2,150,000,000
Provision for uncertain tax positions [member] | 50% Penalties related to cash tax and transfer pricing [member] | Canadian Revenue Agency [member] | Bottom of range [member]
Provisions [Line Items]
Provision for CRA transfer price dispute	970,000,000
Provision for uncertain tax positions [member] | 50% Penalties related to cash tax and transfer pricing [member] | Canadian Revenue Agency [member] | Top of range [member]
Provisions [Line Items]
Provision for CRA transfer price dispute	$ 1,070,000,000

Per share amounts (Details)

Per share amounts (Details) - CAD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Basic earnings (loss) per share computation
Net earnings (loss) attributable to equity holders	$ (53,169)	$ 74,000
Weighted average common shares outstanding	395,829,380	395,796,677
Basic earnings (loss) per common share	$ (0.13)	$ 0.19
Diluted earnings (loss) per share computation
Net earnings (loss) attributable to equity holders	$ (53,169)	$ 74,000
Weighted average common shares outstanding	395,829,380	395,796,677
Dilutive effect of stock options	214,000	258,000
Weighted average common shares outstanding, assuming dilution	396,043,000	396,055,000
Diluted earnings (loss) per common share	$ (0.13)	$ 0.19

Supplemental cash flow inform_3

Supplemental cash flow information (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Changes in non-cash working capital
Accounts receivable	$ 143,717	$ 58,488
Inventories	(376,908)	113,388
Supplies and prepaid expenses	(3,999)	3,612
Accounts payable and accrued liabilities	36,514	(53,477)
Reclamation payments	(17,640)	(32,390)
Other	25,399	6,857
Total	$ (192,917)	$ 96,478

Supplemental cash flow inform_4

Supplemental cash flow information - Financing activities (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	$ 2,875,366
Changes from financing cash flows:
Dividends paid	(31,638)	$ (31,613)
Interest paid	(65,547)	(72,484)
Lease principal payments	(3,716)	(2,904)
Shares issued, stock option plan	5,375	81
Repayment of long-term debt	(400,000)	(500,000)
Proceeds of long-term debt	397,539	0
Total cash changes	(97,987)	(606,920)
Non-cash changes:
Amortization of issue costs	1,284
Dividends declared	31,638
Interest expense	66,495
Right-of-use asset additions	2,221
Right-of-use asset cancellations	(2,165)
Joint operation lease obligations	(1,361)
Shares issued, stock option plan	1,586
Foreign exchange	103
Total non-cash changes	99,801
Ending balance	2,877,180	2,875,366
Long-term borrowings [member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	996,718
Changes from financing cash flows:
Repayment of long-term debt	(400,000)
Proceeds of long-term debt	397,539
Total cash changes	(2,461)
Non-cash changes:
Amortization of issue costs	1,284
Total non-cash changes	1,284
Ending balance	995,541	996,718
Interest payable [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	3,030
Changes from financing cash flows:
Interest paid	(65,280)
Total cash changes	(65,280)
Non-cash changes:
Interest expense	66,228
Total non-cash changes	66,228
Ending balance	3,978	3,030
Lease obligation [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	12,869
Changes from financing cash flows:
Interest paid	(267)
Lease principal payments	(3,716)
Total cash changes	(3,983)
Non-cash changes:
Interest expense	267
Right-of-use asset additions	2,221
Right-of-use asset cancellations	(2,165)
Joint operation lease obligations	(1,361)
Foreign exchange	103
Total non-cash changes	(935)
Ending balance	7,951	12,869
Dividends Payable [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	0
Changes from financing cash flows:
Dividends paid	(31,638)
Total cash changes	(31,638)
Non-cash changes:
Dividends declared	31,638
Total non-cash changes	31,638
Ending balance	0	0
Share capital [Member]
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning balance	1,862,749
Changes from financing cash flows:
Shares issued, stock option plan	5,375
Total cash changes	5,375
Non-cash changes:
Shares issued, stock option plan	1,586
Total non-cash changes	1,586
Ending balance	$ 1,869,710	$ 1,862,749

Share-based compensation plan_2

Share-based compensation plans - Share options number and weighted average price (Details)	12 Months Ended
	Dec. 31, 2020shares$ / shares	Dec. 31, 2019shares$ / shares	Dec. 31, 2020shares$ / shares	Dec. 31, 2019shares$ / shares
Number And Weighted Average Exercise Prices Of Share Options [Abstract]
Beginning of year	8,617,097	8,820,805
Options granted	0	886,740
Options forfeited	(81,991)	(270,025)
Options expired	(1,911,558)	(815,423)
Options exercised	(465,009)	(5,000)
End of year	6,158,539	8,617,097
Weighted average exercisable price - beginning of year | $ / shares	$ 17.44	$ 19.75
Weighted average exercisable price for options granted | $ / shares	0	15.27
Weighted average exercisable price for options forfeited | $ / shares	22.22	22.59
Weighted average exercisable price for options expired | $ / shares	20.14	38.43
Weighted average exercise price for options exercised | $ / shares	11.56	16.38
Weighted average exercisable price - end of year | $ / shares	$ 16.98	$ 17.44
Exercisable			5,076,226	6,290,380
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Number Of Outstanding Share Options	6,158,539	8,617,097	6,158,539	8,617,097
Weighted Average Exercise Price Of Share Options Outstanding In Sharebased Payment Arrangement | $ / shares	$ 16.98	$ 19.75	$ 16.98	$ 17.44
Number Of Share Options Exercisable In Sharebased Payment Arrangement			5,076,226	6,290,380
Options exercisable - Weighted average exercisable price | $ / shares			$ 17.73	$ 18.9
$11.32 - 15.83 [member]
Number And Weighted Average Exercise Prices Of Share Options [Abstract]
End of year	3,060,721
Weighted average exercisable price - end of year | $ / shares	$ 13.72
Exercisable			1,978,408
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Number Of Outstanding Share Options	3,060,721		3,060,721
Options outstanding - Weighted average remaining life	5 years
Weighted Average Exercise Price Of Share Options Outstanding In Sharebased Payment Arrangement | $ / shares	$ 13.72		$ 13.72
Number Of Share Options Exercisable In Sharebased Payment Arrangement			1,978,408
Options exercisable - Weighted average exercisable price | $ / shares			$ 13.85
$15.84 - 26.81 [member]
Number And Weighted Average Exercise Prices Of Share Options [Abstract]
End of year	3,097,818
Weighted average exercisable price - end of year | $ / shares	$ 20.21
Exercisable			3,097,818
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Number Of Outstanding Share Options	3,097,818		3,097,818
Options outstanding - Weighted average remaining life	1 year 9 months 18 days
Weighted Average Exercise Price Of Share Options Outstanding In Sharebased Payment Arrangement | $ / shares	$ 20.21		$ 20.21
Number Of Share Options Exercisable In Sharebased Payment Arrangement			3,097,818
Options exercisable - Weighted average exercisable price | $ / shares			$ 20.21

Share-based compensation plan_3

Share-based compensation plans - equity-settled and cash-settled (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expenses under equity settled plans	$ 9,738	$ 17,469
Expenses (recoveries) under cash-settled plans	27,241	(1,437)
Stock Option Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expenses under equity settled plans	1,011	4,418
Performance Share Unit Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expenses under equity settled plans	2,650	7,245
Expenses (recoveries) under cash-settled plans	20,287	0
Restricted Share Unit Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expenses under equity settled plans	2,903	2,679
Expenses (recoveries) under cash-settled plans	1,849	0
Employee Share Ownership Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expenses under equity settled plans	3,174	3,127
Deferred Share Unit Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expenses (recoveries) under cash-settled plans	3,765	(1,001)
Phantom Stock Option Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Expenses (recoveries) under cash-settled plans	$ 1,340	$ (436)

Share-based compensation plan_4

Share-based compensation plans - Inputs used in the measurement - Equity (Details)	12 Months Ended
	Dec. 31, 2020shares$ / shares	Dec. 31, 2019shares$ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of options granted | shares	0	886,740
Average strike price	$ 0	$ 15.27
Restricted Share Unit Plan Equity Settled [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of options granted | shares	283,426
Average strike price	$ 11.45
Expected forfeitures	13.00%
Weighted average grant date fair values	$ 11.45

Share-based compensation plan_5

Share-based compensation plans - Inputs used in the measurement - Cash (Details)	12 Months Ended
	Dec. 31, 2020CAD ($)sharesyr$ / shares	Dec. 31, 2019shares$ / shares	Dec. 31, 2018shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of options granted | shares	0	886,740
Average strike price	$ 0	$ 15.27
Number of options, reporting date | shares	6,158,539	8,617,097	8,820,805
Average strike price, reporting date	$ 17.73	$ 18.9
Performance Share Unit Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of options granted | shares	636,570
Expected vesting	102.00%
Average strike price	$ 0
Expected dividend | $	$ 0
Expected volatility	0.00%
Risk-free interest rate	0.00%
Expected life of option | yr	3
Expected forfeitures	12.00%
Weighted average grant date fair values	$ 11.45
Number of options, reporting date | shares	1,720,636
Expected vesting, reporting date	129.00%
Expected dividend, reporting date | $	$ 0
Expected volatility, reporting date	22.00%
Risk free interest rate, reporting date	0.10%
Expected life of option, reporting date | yr	1
Expected forfeitures, reporting date	11.00%
Weighted average share price, reporting date	$ 22.01
Restricted Share Unit Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of options granted | shares	423,180
Expected vesting	0.00%
Average strike price	$ 0
Expected dividend | $	$ 0
Expected volatility	0.00%
Risk-free interest rate	0.00%
Expected life of option | yr	3
Expected forfeitures	12.00%
Weighted average grant date fair values	$ 11.45
Number of options, reporting date | shares	425,176
Expected vesting, reporting date	0.00%
Expected dividend, reporting date | $	$ 0
Expected volatility, reporting date	0.00%
Risk free interest rate, reporting date	0.00%
Expected life of option, reporting date | yr	2.2
Expected forfeitures, reporting date	12.00%
Weighted average share price, reporting date	$ 17.05
Phantom Stock Option Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of options granted | shares	112,140
Expected vesting	0.00%
Average strike price	$ 11.61
Expected dividend | $	$ 0.08
Expected volatility	39.00%
Risk-free interest rate	0.60%
Expected life of option | yr	4
Expected forfeitures	8.00%
Weighted average grant date fair values	$ 2.85
Number of options, reporting date | shares	422,291
Expected vesting, reporting date	0.00%
Average strike price, reporting date	$ 15.66	$ 16.48
Expected dividend, reporting date | $	$ 0.08
Expected volatility, reporting date	41.00%
Risk free interest rate, reporting date	0.30%
Expected life of option, reporting date | yr	3.4
Expected forfeitures, reporting date	7.00%
Weighted average share price, reporting date	$ 5.43

Share-based compensation plan_6

Share-based compensation plans - Narrative (Details)	12 Months Ended
	Dec. 31, 2020CAD ($)sharesNumber_employees$ / shares	Dec. 31, 2019CAD ($)sharesNumber_employees$ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Stock options held	5,076,226	6,290,380
Options exercisable - Weighted average exercisable price | $ / shares	$ 17.73	$ 18.9
Modification of sharebased payments restricted and performance shares | $		$ (8,369,000)
Stock Option Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	The options carry vesting periods of one to three years, and expire eight years from the date granted
Authorized shares	43,017,198
Outstanding shares	28,340,298
Performance Share Unit Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	three-year vesting period
Stock options held	1,720,636	1,465,618
Restricted Share Unit Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	The RSUs carry vesting periods of one to three years
Stock options held	927,462	443,274
Employee Share Ownership Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	Shares purchased with Company contributions and with dividends paid on such shares become unrestricted 12 months from the date on which such shares were purchased
Employers contribution per employee	Under the plan, employees have the opportunity to participate in the program to a maximum of 6% of eligible earnings each year with Cameco matching the first 3% of employee-paid shares by 50%. Cameco contributes $1,000 of shares annually to each employee that is enrolled in the plan
Number of participants | Number_employees	2,257	2,253
Total number of shares purchased	248,837	235,915
Total amount of employer's contribution | $	$ 3,174,000	$ 3,127,000
Deferred Share Unit Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	Each DSU fully vests upon award
Stock options held	541,827	474,266
Description of method of settlement for share-based payment arrangement	60% of each director’s annual retainer is paid in DSUs. In addition, on an annual basis, directors can elect to receive 25%, 50%, 75% or 100% of the remaining 40% of their annual retainer and any additional fees in the form of DSUs
Phantom Stock Option Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	vest over three years and expire eight years from the date granted
Stock options held	422,291	406,270
Options exercisable - Weighted average exercisable price | $ / shares	$ 15.66	$ 16.48
Phantom Stock Option Plan [member] | Bottom of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Exercise prices range | $ / shares	11.32	11.32
Phantom Stock Option Plan [member] | Top of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Exercise prices range | $ / shares	$ 26.81	$ 26.81
Cash Settled Plan [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Liabilities from share-based payment transactions | $	$ 38,354,000	$ 14,577,000

Pension and other post-retire_3

Pension and other post-retirement benefits - Defined benefit plans (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Actuarial loss (gain) arising from:
Administration	$ 145,344	$ 124,869
Pension plans [member]
Disclosure of benefit plans [line items]
Current service cost	1,977	1,586
Interest income or cost	(1,476)	(1,545)
Return on assets excluding interest income	(130)	(280)
Pension plans [member] | Plan assets [member]
Disclosure of benefit plans [line items]
Fair value of plan assets, beginning of year	6,806	7,177
Interest income or cost	197	262
Return on assets excluding interest income	130	280
Employer contributions	0	0
Actuarial loss (gain) arising from:
Benefits paid	(915)	(912)
Administration	(1)	(1)
Fair value of plan assets, end of year	6,217	6,806
Pension plans [member] | Defined benefit obligations [member]
Disclosure of benefit plans [line items]
Defined benefit obligation, beginning of year	62,588	54,271
Current service cost	1,977	1,586
Interest income or cost	1,673	1,807
Actuarial loss (gain) arising from:
- demographic assumptions	0	0
- financial assumptions	6,323	6,925
- experience adjustment	350	777
Past service cost	0	0
Benefits paid	(1,765)	(1,705)
Foreign exchange	973	(1,073)
Defined benefit obligation, end of year	72,119	62,588
Defined benefit liability	(65,902)	(55,782)
Other Benefit Plans [Member]
Disclosure of benefit plans [line items]
Current service cost	1,010	817
Interest income or cost	(792)	(841)
Return on assets excluding interest income	0	0
Actuarial loss (gain) arising from:
Past service cost	0	0
Other Benefit Plans [Member] | Defined benefit obligations [member]
Disclosure of benefit plans [line items]
Defined benefit obligation, beginning of year	24,955	21,161
Current service cost	1,010	817
Interest income or cost	792	841
Actuarial loss (gain) arising from:
- demographic assumptions	102	0
- financial assumptions	2,013	2,877
- experience adjustment	(2,236)	114
Past service cost	0	0
Benefits paid	(809)	(855)
Foreign exchange	0	0
Defined benefit obligation, end of year	25,827	24,955
Defined benefit liability	$ (25,827)	$ (24,955)

Pension and other post-retire_4

Pension and other post-retirement benefits - percentages of the total fair value of assets (Details) - Pension plans [member] - CAD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Disclosure of benefit plans [line items]
The percentages of the total fair value of assets	[1]	100.00%	100.00%
Description of the refundable tax account held by CRA		equal to half of the sum of the realized investment income plus employer contributions less half of the benefits paid by the plan
Related Parties [member]
Disclosure of benefit plans [line items]
Defined benefit plan assets		$ 0	$ 0
Canadian Equity Securities [member]
Disclosure of benefit plans [line items]
The percentages of the total fair value of assets		8.00%	9.00%
US equity securities [Member]
Disclosure of benefit plans [line items]
The percentages of the total fair value of assets		12.00%	12.00%
Global Equity Securities [member]
Disclosure of benefit plans [line items]
The percentages of the total fair value of assets		8.00%	9.00%
Canadian Fixed Income [member]
Disclosure of benefit plans [line items]
The percentages of the total fair value of assets		31.00%	30.00%
Other [member]
Disclosure of benefit plans [line items]
The percentages of the total fair value of assets	[2]	41.00%	40.00%
[1]	The defined benefit plan assets contain no material amounts of related p arty assets at December 31, 2020 and 2019 respectively.
[2]	Relates mainly to the value of the refundable tax account held by the Canada Revenue Agency. The refundable total is approximately equal to half of the sum of the realized investment income plus employer contributions less half of the benefits paid by the plan .

Pension and other post-retire_5

Pension and other post-retirement benefits - components of net pension and other benefit expense (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of benefit plans [line items]
Defined benefit expense	$ 5,256	$ 4,790
Defined contribution pension expense	12,410	11,767
Employee benefit expense	322,669	312,561
Pension plans [member]
Disclosure of benefit plans [line items]
Current service cost	1,977	1,586
Interest income or cost	1,476	1,545
Administration cost	1	1
Defined benefit expense	3,454	3,132
Defined contribution pension expense	12,410	11,767
Employee benefit expense	15,864	14,899
Amount of actuarial losses (gains) recognized in other comprehensive income
Actuarial loss (gain)	6,673	7,702
Return on assets excluding interest income	(130)	(280)
Total actuarial losses (gains) recognized in other comprehensive income	6,543	7,422
Other Benefit Plans [Member]
Disclosure of benefit plans [line items]
Current service cost	1,010	817
Interest income or cost	792	841
Past service cost	0	0
Administration cost	0	0
Defined benefit expense	1,802	1,658
Defined contribution pension expense	0	0
Employee benefit expense	1,802	1,658
Amount of actuarial losses (gains) recognized in other comprehensive income
Actuarial loss (gain)	(121)	2,991
Return on assets excluding interest income	0	0
Total actuarial losses (gains) recognized in other comprehensive income	$ (121)	$ 2,991

Pension and other post-retire_6

Pension and other post-retirement benefits - Assumptions and 1% change (Details) - CAD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension plans [member]
Assumptions defined benefit obligation and net pension and other benefit expense
Discount rate - obligation	2.40%	3.00%
Discount rate - expense	3.00%	3.70%
Rate of compensation increase	2.90%	3.00%
Pension plans [member] | Discount rate [member]
Sensitivity analysis of actuarial assumptions
Increase in actuarial assumption by	1.00%
Increase in defined benefit obligation	$ 12,766,000
Decrease in actuarial assumption by	1.00%
Decrease in defined benefit obligation	$ (9,778,000)
Pension plans [member] | Rate of compensation increase [member]
Sensitivity analysis of actuarial assumptions
Increase in actuarial assumption by	1.00%
Increase in defined benefit obligation	$ 3,009,000
Decrease in actuarial assumption by	1.00%
Decrease in defined benefit obligation	$ (2,772,000)
Pension plans [member] | Increase of one year in the expected lifetime [member]
Sensitivity analysis of actuarial assumptions
Increase in defined benefit obligation	$ 2,030,000
Other Benefit Plans [Member]
Assumptions defined benefit obligation and net pension and other benefit expense
Discount rate - obligation	2.50%	3.10%
Discount rate - expense	3.10%	3.90%
Initial health care cost trend rate	5.00%	6.00%
Cost trend rate declines to	5.00%	5.00%
Year the rate reaches its final level	2021	2022
Dental care cost trend rate	4.50%	5.00%
Other Benefit Plans [Member] | Discount rate [member]
Sensitivity analysis of actuarial assumptions
Increase in actuarial assumption by	1.00%
Increase in defined benefit obligation	$ 4,138,000
Decrease in actuarial assumption by	1.00%
Decrease in defined benefit obligation	$ (3,270,000)

Pension and other post-retire_7

Pension and other post-retirement benefits - Narrative (Details) - CAD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of benefit plans [line items]
Description of Retirement benefit plan	Under the supplemental executive pension plan (SEPP), Cameco provides a lump sum benefit equal to the present value of a lifetime pension benefit based on the executive’s length of service and final average earnings.
Description of Retirement benefits promised to participants	The plan provides for unreduced benefits to be paid at the normal retirement age of 65, however unreduced benefits could be paid if the executive was at least 60 years of age and had 20 years of service at retirement. This program provides for a benefit determined by a formula based on earnings and service, reduced by the benefits payable under the registered base plan.
2021 [Member]
Disclosure of benefit plans [line items]
Contributions and fees payable	$ 1,785,000
Pension plans [member]
Disclosure of benefit plans [line items]
Description of the refundable tax account held by CRA	equal to half of the sum of the realized investment income plus employer contributions less half of the benefits paid by the plan
Weighted Average Length Of Time Of Defined Benefit Obligation	20 years 6 months	20 years
Pension plans [member] | Increase of one year in the expected lifetime [member]
Disclosure of benefit plans [line items]
Change in defined benefit obligations due to increase in actuarial assumption	$ 2,030,000
Other Benefit Plans [Member]
Disclosure of benefit plans [line items]
Weighted Average Length Of Time Of Defined Benefit Obligation	14 years 2 months 12 days	15 years 2 months 12 days

Financial instruments - related

Financial instruments - related risk management (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of detailed information about financial instruments [line items]
Financial assets	$ 1,237,825	$ 1,425,387
Financial liabilities	(1,241,874)	(1,203,910)
Gain (loss) on derivatives	36,577	32,269
Finance income	10,835	29,760
Disclosure of credit risk exposure [abstract]
Cash and cash equivalents	918,382	1,062,431	$ 711,528
Short-term investments	24,985	0
Derivative assets	$ 45,605	10,504
USD currency risk [member]
Disclosure of detailed information about financial instruments [line items]
Percentage increase or decrease in CAD$	5.00%
USD currency risk [member] | Cash and cash equivalents [member]
Disclosure of detailed information about financial instruments [line items]
Financial assets	$ 86,985
Gain (loss), foreign exchange	4,349
USD currency risk [member] | Accounts receivable [Member]
Disclosure of detailed information about financial instruments [line items]
Financial assets	136,894
Gain (loss), foreign exchange	6,845
USD currency risk [member] | Accounts Payable and Accrued Liabilities [Member]
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	(72,576)
Gain (loss), foreign exchange	(3,629)
USD currency risk [member] | Net foreign currency derivatives [Member]
Disclosure of detailed information about financial instruments [line items]
Financial assets	40,872
Gain (loss), foreign exchange	(38,811)
Credit risk [member]
Disclosure of credit risk exposure [abstract]
Cash and cash equivalents	918,382	1,062,431
Short-term investments	24,985	0
Accounts receivable	166,788	323,430
Derivative assets	$ 45,605	$ 10,504

Financial Instruments - Exposur

Financial Instruments - Exposure to credit risk receivables (Details) - CAD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [line items]
Trade receivables	$ 166,054	$ 321,638
Loss allowance	0
Net	166,054
Investment grade rating [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	160,093
Non-investment grade rating [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	$ 5,961

Financial Instruments - Aging o

Financial Instruments - Aging of trade receivables (Details) - CAD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [line items]
Trade receivables	$ 166,054	$ 321,638
Corporate customers [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	161,456
Other customers [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	4,598
Current (not past due)
Disclosure of detailed information about financial instruments [line items]
Trade receivables	162,929
Current (not past due) | Corporate customers [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	159,280
Current (not past due) | Other customers [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	3,649
1-30 days past due
Disclosure of detailed information about financial instruments [line items]
Trade receivables	567
1-30 days past due | Corporate customers [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	133
1-30 days past due | Other customers [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	434
More than 30 days past due
Disclosure of detailed information about financial instruments [line items]
Trade receivables	2,558
More than 30 days past due | Corporate customers [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	2,043
More than 30 days past due | Other customers [Member]
Disclosure of detailed information about financial instruments [line items]
Trade receivables	$ 515

Financial instruments - Liquidi

Financial instruments - Liquidity Risk Tables (Details) - CAD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Disclosure of maturity analysis for financial liabilities [abstract]
Carrying amount	$ 1,241,874	$ 1,203,910
Contractual cash flows	1,246,907
Total interest payments on long-term debt	267,905
Due in less than one year [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	238,964
Total interest payments on long-term debt	37,840
Due in one to three years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	6,971
Total interest payments on long-term debt	75,680
Due in three to five years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	500,972
Total interest payments on long-term debt	44,255
Due after five years [member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	500,000
Total interest payments on long-term debt	110,130
Accounts Payable and Accrued Liabilities [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Carrying amount	233,649
Contractual cash flows	233,649
Accounts Payable and Accrued Liabilities [Member] | Due in less than one year [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	233,649
Accounts Payable and Accrued Liabilities [Member] | Due in one to three years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	0
Accounts Payable and Accrued Liabilities [Member] | Due in three to five years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	0
Accounts Payable and Accrued Liabilities [Member] | Due after five years [member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	0
Long-Term Debt [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Carrying amount	995,541
Contractual cash flows	1,000,000
Long-Term Debt [Member] | Due in less than one year [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	0
Long-Term Debt [Member] | Due in one to three years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	0
Long-Term Debt [Member] | Due in three to five years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	500,000
Long-Term Debt [Member] | Due after five years [member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	500,000
Foreign currency contracts [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Carrying amount	4,733
Contractual cash flows	4,733
Foreign currency contracts [Member] | Due in less than one year [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	1,658
Foreign currency contracts [Member] | Due in one to three years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	3,075
Foreign currency contracts [Member] | Due in three to five years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	0
Foreign currency contracts [Member] | Due after five years [member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	0
Lease obligation [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Carrying amount	7,951
Contractual cash flows	8,525
Lease obligation [Member] | Due in less than one year [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	3,657
Lease obligation [Member] | Due in one to three years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	3,896
Lease obligation [Member] | Due in three to five years [Member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	972
Lease obligation [Member] | Due after five years [member]
Disclosure of maturity analysis for financial liabilities [abstract]
Contractual cash flows	0
Unsecured revolving credit facility [Member]
Disclosure of detailed information about borrowings [line items]
Maximum borrowing capacity	1,000,000
Committed and outstanding	0
Available borrowing facility	1,000,000
Letter of credit facilities [Member]
Disclosure of detailed information about borrowings [line items]
Maximum borrowing capacity	1,698,340
Committed and outstanding	1,596,488
Available borrowing facility	$ 101,852

Financial instruments - Measure

Financial instruments - Measurement of fair values (Details) - CAD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financial assets [Abstract]
Cash and cash equivalents		$ 918,382	$ 1,062,431	$ 711,528
Short-term investments		24,985	0
Derivative assets		45,605	10,504
Accounts receivable		204,980	328,044
Investments in equity securities	[1]	43,873	24,408
Financial assets		1,237,825	1,425,387
Financial liabilities [Abstract]
Accounts payable and accrued liabilities		233,649	181,799
Lease obligation		7,951	12,869
Derivative liabilities		4,733	12,524
Long-term debt		995,541	996,718
Financial liabilities		1,241,874	1,203,910
Net		(4,049)	221,477
Foreign currency contracts [Member]
Financial assets [Abstract]
Derivative assets		45,605	8,191
Financial liabilities [Abstract]
Derivative liabilities		4,733	12,524
Interest rate contracts [member]
Financial assets [Abstract]
Derivative assets		0	2,313
Financial liabilities [Abstract]
Derivative liabilities		0	0
Fair value through profit or loss [member]
Financial liabilities [Abstract]
Financial liabilities		4,733	12,524
Net		40,872	(2,020)
Fair value through profit or loss [member] | Foreign currency contracts [Member]
Financial liabilities [Abstract]
Derivative liabilities		4,733	12,524
Fair value through profit or loss [member] | Interest rate contracts [member]
Financial liabilities [Abstract]
Derivative liabilities		0	0
Financial liabilities at amortised cost category [Member]
Financial liabilities [Abstract]
Accounts payable and accrued liabilities		233,649	181,799
Lease obligation		7,951	12,869
Long-term debt		995,541	996,718
Financial liabilities		1,237,141	1,191,386
Net		(88,794)	199,089
Fair value through profit or loss [member]
Financial assets [Abstract]
Financial assets		45,605	10,504
Fair value through profit or loss [member] | Foreign currency contracts [Member]
Financial assets [Abstract]
Derivative assets		45,605	8,191
Fair value through profit or loss [member] | Interest rate contracts [member]
Financial assets [Abstract]
Derivative assets		0	2,313
Financial assets at amortised cost category [Member]
Financial assets [Abstract]
Cash and cash equivalents		918,382	1,062,431
Short-term investments		24,985	0
Accounts receivable		204,980	328,044
Financial assets		1,148,347	1,390,475
Financial liabilities [Abstract]
Net		(88,794)	199,089
Investments in equity instruments measured at FVOCI [Member]
Financial assets [Abstract]
Investments in equity securities		43,873	24,408
Financial assets		43,873	24,408
Financial liabilities [Abstract]
Net		$ 43,873	$ 24,408
[1]	At January 1, 2018, Cameco designated the investments shown below as equity securities at FVOCI because these equity securities represent investments that the Company intends to hold for the long term for strategic purposes . There were no dividends recognized on any of these investments during the year.

Financial instruments - Measu_2

Financial instruments - Measurement of fair values hierarchy levels (Details) - CAD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [line items]
Derivative assets		$ 45,605	$ 10,504
Investments in equity securities	[1]	43,873	24,408
Derivative liabilities		(4,733)	(12,524)
Long-term debt		(995,541)	(996,718)
Net financial instruments		(910,796)	(974,330)
Foreign currency contracts [Member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets		45,605	8,191
Derivative liabilities		(4,733)	(12,524)
Interest rate contracts [member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets		0	2,313
Derivative liabilities		0	0
Level 1 of fair value hierarchy [member]
Disclosure of detailed information about financial instruments [line items]
Investments in equity securities		43,873	24,408
Net financial instruments		43,873	24,408
Level 2 of fair value hierarchy [member]
Disclosure of detailed information about financial instruments [line items]
Long-term debt		(1,173,280)	(1,111,923)
Net financial instruments		(1,132,408)	(1,113,943)
Level 2 of fair value hierarchy [member] | Foreign currency contracts [Member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets		45,605	8,191
Derivative liabilities		(4,733)	(12,524)
Level 2 of fair value hierarchy [member] | Interest rate contracts [member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets		0	2,313
Derivative liabilities		0	0
Fair value [member]
Disclosure of detailed information about financial instruments [line items]
Investments in equity securities		43,873	24,408
Long-term debt		(1,173,280)	(1,111,923)
Net financial instruments		(1,088,535)	(1,089,535)
Fair value [member] | Foreign currency contracts [Member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets		45,605	8,191
Derivative liabilities		(4,733)	(12,524)
Fair value [member] | Interest rate contracts [member]
Disclosure of detailed information about financial instruments [line items]
Derivative assets		0	2,313
Derivative liabilities		$ 0	$ 0
[1]	At January 1, 2018, Cameco designated the investments shown below as equity securities at FVOCI because these equity securities represent investments that the Company intends to hold for the long term for strategic purposes . There were no dividends recognized on any of these investments during the year.

Financial instruments - Derivat

Financial instruments - Derivatives (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about financial instruments [line items]
Net	$ 40,872	$ (2,020)
Gain (loss)	36,577	32,269
Current portion of other liabilities [member]
Disclosure of detailed information about financial instruments [line items]
Net	(1,658)	(7,505)
Other liabilities [Member]
Disclosure of detailed information about financial instruments [line items]
Net	(3,075)	(5,019)
Current portion of long-term receivables, investments and other [member]
Disclosure of detailed information about financial instruments [line items]
Net	16,466	4,144
Long-term receivables, investments and other [Member]
Disclosure of detailed information about financial instruments [line items]
Net	29,139	6,360
Foreign currency contracts [Member]
Disclosure of detailed information about financial instruments [line items]
Net	40,872	(4,333)
Gain (loss)	30,600	31,863
Interest rate swap contracts [member]
Disclosure of detailed information about financial instruments [line items]
Net	0	2,313
Gain (loss)	5,977	2,068
Uranium contracts [Member]
Disclosure of detailed information about financial instruments [line items]
Gain (loss)	$ 0	$ (1,662)

Financial instruments - Narrati

Financial instruments - Narrative (Details) - CAD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Nov. 16, 2020	Dec. 31, 2018
Disclosure of detailed information about financial instruments [line items]
Gain (loss)	$ 36,577,000	$ 32,269,000
Cash and cash equivalents	918,382,000	1,062,431,000		$ 711,528,000
Short-term investments	24,985,000	$ 0
Pledged cash as security	$ 190,140,000
Bottom of range [member]
Disclosure of detailed information about financial instruments [line items]
Quoted market yields	0.30%	1.70%
Top of range [member]
Disclosure of detailed information about financial instruments [line items]
Quoted market yields	1.10%	1.80%
Interest rate swap contracts [member]
Disclosure of detailed information about financial instruments [line items]
Gain (loss)	$ 5,977,000	$ 2,068,000
Credit risk [member]
Disclosure of detailed information about financial instruments [line items]
Cash and cash equivalents	918,382,000	1,062,431,000
Short-term investments	$ 24,985,000	$ 0
Interest rate risk [member]
Disclosure of detailed information about financial instruments [line items]
Proportion of outstanding debt that carries fixed rate	100.00%	85.00%
Interest rate risk [member] | Interest rate swap contracts [member]
Disclosure of detailed information about financial instruments [line items]
Fair value of Cameco's interest rate swap assets	$ 0	$ 2,313,000	$ 7,330,000
Interest rate risk [member] | Interest rate swap contracts [member] | Series E senior unsecured debenture [Member]
Disclosure of detailed information about financial instruments [line items]
Notional amount		$ 150,000,000
Interest rate risk [member] | Interest rate swap contracts [member] | Series E senior unsecured debenture [Member] | Floating interest rate [member]
Disclosure of detailed information about financial instruments [line items]
Interest rate basis		the three-month Canada Dealer Offered Rate
Margin rate		1.20%
Interest rate risk [member] | Interest rate swap contracts [member] | Series E senior unsecured debenture [Member] | Fixed interest rate [member]
Disclosure of detailed information about financial instruments [line items]
Interest rate		3.75%

Capital management (Details)

Capital management (Details) - CAD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure of objectives policies and processes for managing capital abstract
Long-term debt	$ 995,541	$ 996,718
Cash and cash equivalents	(918,382)	(1,062,431)	$ (711,528)
Short-term investments	(24,985)	0
Net debt	52,174	(65,713)
Non-controlling interest	206	238
Shareholders' equity	4,958,355	4,994,725
Total shareholders' equity	4,958,561	4,994,963	$ 4,993,592
Total capital	$ 5,010,735	$ 4,929,250

Segmented information - Narrati

Segmented information - Narrative (Details) - CAD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Operating Segments [Line Items]
Segment information	Cameco has two reportable segments: uranium and fuel services. Cameco's reportable segments are strategic business units with different products, processes and marketing strategies.
Uranium [Member]
Disclosure Of Operating Segments [Line Items]
Care and maintenance	$ 195,972,000	$ 153,924,000
Uranium [Member] | Cigar Lake [Member]
Disclosure Of Operating Segments [Line Items]
COVID-19 care and maintenance	45,988,000
Fuel Service [Member]
Disclosure Of Operating Segments [Line Items]
COVID-19 care and maintenance	$ 8,992,000

Segmented information - Busines

Segmented information - Business segments (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Operating Segments [Line Items]
Revenue	$ 1,800,073	$ 1,862,925
Cost of products and services sold	1,484,962	1,345,551
Depreciation and amortization	208,662	275,749
Cost of sales	1,693,624	1,621,300
Gross profit	106,449	241,625
Administration	145,344	124,869
Exploration	10,873	13,686
Research and development	3,965	6,058
Other operating expense	23,921	2,732
Loss on disposal of assets	1,072	1,869
Finance costs	96,133	98,622
Gain on derivatives	(36,577)	(32,269)
Finance income	(10,835)	(29,760)
Share of earnings from equity-accounted investee	(36,476)	(45,360)
Other expense (income)	(51,440)	(33,840)
Income tax expense (recovery)	13,666	61,077
Earnings (loss) before income taxes	(39,531)	135,018
Net earnings (loss)	(53,197)	73,941
Capital expenditures for the year	77,462	75,211
Uranium [Member]
Disclosure Of Operating Segments [Line Items]
Revenue	1,411,770	1,413,809
Cost of products and services sold	1,244,049	1,041,922
Depreciation and amortization	154,560	218,832
Cost of sales	1,398,609	1,260,754
Gross profit	13,161	153,055
Administration	0	0
Exploration	10,873	13,686
Research and development	0	0
Other operating expense	23,921	2,732
Loss on disposal of assets	667	1,869
Finance costs	0	0
Gain on derivatives	0	0
Finance income	0	0
Share of earnings from equity-accounted investee	(36,476)	(45,360)
Other expense (income)	(202)	(52,801)
Earnings (loss) before income taxes	14,378	232,929
Capital expenditures for the year	46,697	48,092
Fuel Service [Member]
Disclosure Of Operating Segments [Line Items]
Revenue	377,296	370,277
Cost of products and services sold	237,656	234,423
Depreciation and amortization	43,190	45,856
Cost of sales	280,846	280,279
Gross profit	96,450	89,998
Administration	0	0
Exploration	0	0
Research and development	0	0
Other operating expense	0	0
Loss on disposal of assets	405	0
Finance costs	0	0
Gain on derivatives	0	0
Finance income	0	0
Share of earnings from equity-accounted investee	0	0
Other expense (income)	0	0
Earnings (loss) before income taxes	96,045	89,998
Capital expenditures for the year	30,760	27,117
Other Segment [Member]
Disclosure Of Operating Segments [Line Items]
Revenue	11,007	78,839
Cost of products and services sold	3,257	69,206
Depreciation and amortization	10,912	11,061
Cost of sales	14,169	80,267
Gross profit	(3,162)	(1,428)
Administration	145,344	124,869
Exploration	0	0
Research and development	3,965	6,058
Other operating expense	0	0
Loss on disposal of assets	0	0
Finance costs	96,133	98,622
Gain on derivatives	(36,577)	(32,269)
Finance income	(10,835)	(29,760)
Share of earnings from equity-accounted investee	0	0
Other expense (income)	(51,238)	18,961
Earnings (loss) before income taxes	(149,954)	(187,909)
Capital expenditures for the year	$ 5	$ 2

Segmented information - Geograp

Segmented information - Geographical segment (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of geographical areas [line items]
Revenue	$ 1,800,073	$ 1,862,925
Non-current assets	3,827,379	3,781,082
Canada [member]
Disclosure of geographical areas [line items]
Revenue	622,317	567,730
Non-current assets	3,260,144	3,267,376
Australia [Member]
Disclosure of geographical areas [line items]
Non-current assets	421,836	392,500
United States [Member]
Disclosure of geographical areas [line items]
Revenue	1,177,756	1,295,195
Non-current assets	145,328	121,102
Kazakhstan [Member]
Disclosure of geographical areas [line items]
Non-current assets	55	80
Germany [Member]
Disclosure of geographical areas [line items]
Non-current assets	$ 16	$ 24

Segmented information - Major c

Segmented information - Major customers (Details) - CAD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of major customers [line items]
Revenue	$ 1,800,073,000	$ 1,862,925,000
Major customer(s) of Cameco's uranium and fuel services segments [member]
Disclosure of major customers [line items]
Revenue	$ 457,560,000	$ 422,740,000
Percentage of entity's revenue	25.00%	24.00%
Information about major customers	As customers are relatively few in number, accounts receivable from any individual customer may periodically exceed 10% of accounts receivable depending on delivery schedule.

Group entities (Details)

Group entities (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
JV Inkai Associate [Member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiaries	40.00%	40.00%
Principal place of business of associate	Kazakhstan
Cameco Fuel Manufacturing Inc. [member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiaries	100.00%	100.00%
Principal place of business of subsidiary	Canada
Cameco Marketing Inc. [member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiaries	100.00%	100.00%
Principal place of business of subsidiary	Canada
Cameco Inc. [member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiaries	100.00%	100.00%
Principal place of business of subsidiary	US
Power Resources, Inc. [member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiaries	100.00%	100.00%
Principal place of business of subsidiary	US
Crow Butte Resources, Inc. [member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiaries	100.00%	100.00%
Principal place of business of subsidiary	US
NUKEM, Inc. [member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiaries	100.00%	100.00%
Principal place of business of subsidiary	US
Cameco Australia Pty. Ltd. [member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiaries	100.00%	100.00%
Principal place of business of subsidiary	Australia
Cameco Europe Ltd. [member]
Disclosure of subsidiaries [line items]
Ownership interest in subsidiaries	100.00%	100.00%
Principal place of business of subsidiary	Switzerland

Joint operations (Details)

Joint operations (Details) - CAD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Disclosure of joint operations [line items]
Total assets	$ 7,580,831	$ 7,427,248
Joint operations [member]
Disclosure of joint operations [line items]
Total assets	2,916,418	2,925,279
Total liabilities	$ 359,532	307,090
McArthur River [Member]
Disclosure of joint operations [line items]
Ownership	69.81%
Principal place of business	Canada
Total assets	$ 1,027,617	1,046,556
Total liabilities	$ 34,597	32,132
Key Lake [Member]
Disclosure of joint operations [line items]
Ownership	83.33%
Principal place of business	Canada
Total assets	$ 560,845	524,324
Total liabilities	$ 278,331	227,562
Cigar Lake [Member]
Disclosure of joint operations [line items]
Ownership	50.03%
Principal place of business	Canada
Total assets	$ 1,327,956	1,354,399
Total liabilities	$ 46,604	$ 47,396

Related parties (Details)

Related parties (Details)	12 Months Ended
	Dec. 31, 2020CAD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019CAD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2020USD ($)
Disclosure of transactions between related parties [line items]
Short-term employee benefits	$ 21,676,000		$ 21,225,000
Share-based compensation	26,230,000		12,034,000
Post-employment benefits	6,041,000		5,542,000
Termination benefits	430,000		272,000
Total compensation	54,377,000		39,073,000
Dividends from equity-accounted investee	$ 54,404,000		14,079,000
Key management personnel of entity or parent [member]
Disclosure of transactions between related parties [line items]
Description of any retirement benefit plan termination terms	Upon resignation at the Company’s request, they are entitled to termination benefits of up to the lesser of 18 to 24 months or the period remaining until age 65. The termination benefits include gross salary plus the target short-term incentive bonus for the year in which termination occurs	Upon resignation at the Company’s request, they are entitled to termination benefits of up to the lesser of 18 to 24 months or the period remaining until age 65. The termination benefits include gross salary plus the target short-term incentive bonus for the year in which termination occurs
Inkai [Member]
Disclosure of transactions between related parties [line items]
Loan facilities					$ 175,000,000
Interest rate basis	LIBOR plus 2%	LIBOR plus 2%
Interest income			1,878,000
Loan oustanding	$ 0				$ 0
Purchases	148,169,000	$ 111,886,000	112,861,000	$ 84,827,000
Dividends from equity-accounted investee	$ 54,404,000	$ 40,621,000	$ 14,079,000	$ 10,635,000