Basis of Presentation (Policies)	9 Months Ended
Sep. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation	The unaudited interim consolidated financial statements have been prepared in conformity with United States generally accepted accounting principles (or GAAP). They include the accounts of Teekay Corporation (or Teekay), which is incorporated under the laws of the Republic of the Marshall Islands, and its wholly-owned or controlled subsidiaries (collectively, the Company). Certain of Teekay’s significant non-wholly owned subsidiaries are consolidated in these financial statements even though Teekay owns less than a 50% ownership interest in the subsidiaries. These significant subsidiaries include the following publicly traded subsidiaries (collectively, the Public Subsidiaries): Teekay LNG Partners L.P. (or Teekay LNG); Teekay Tankers Ltd. (or Teekay Tankers); and, until September 25, 2017, Teekay Offshore Partners L.P. (or Teekay Offshore). On September 25, 2017, Teekay, Teekay Offshore and Brookfield Business Partners L.P. together with its institutional partners (collectively, Brookfield) finalized a strategic partnership (or the Brookfield Transaction) which resulted in the deconsolidation of Teekay Offshore as of that date (see Note 3). Although Teekay owned less than 50% of Teekay Offshore, Teekay maintained control of Teekay Offshore until September 25, 2017 by virtue of its 100% ownership interest in the general partner of Teekay Offshore, which is a master limited partnership. In connection with Brookfield's acquisition of a 49% interest in Teekay Offshore's general partner, Teekay Offshore GP LLC (or TOO GP), Teekay and Brookfield entered into an amended limited liability company agreement whereby Brookfield obtained certain participatory rights in the management of TOO GP, which resulted in Teekay deconsolidating Teekay Offshore for accounting purposes on September 25, 2017. Subsequent to the closing of the Brookfield Transaction, Teekay has significant influence over Teekay Offshore and accounts for its investment in Teekay Offshore using the equity method. Certain information and footnote disclosures required by GAAP for complete annual financial statements have been omitted and, therefore, these unaudited interim consolidated financial statements should be read in conjunction with the Company’s audited financial statements for the year ended December 31, 2016, included in the Company’s Annual Report on Form 20-F, filed with the U.S. Securities and Exchange Commission (or SEC) on April 12, 2017. In the opinion of management, these unaudited interim consolidated financial statements reflect all adjustments, consisting solely of a normal recurring nature, necessary to present fairly, in all material respects, the Company’s consolidated financial position, results of operations, cash flows and changes in total equity for the interim periods presented. The results of operations for the three and nine months ended September 30, 2017, are not necessarily indicative of those for a full fiscal year. Significant intercompany balances and transactions have been eliminated upon consolidation. In addition, certain of the comparative figures have been reclassified to conform to the presentation adopted in the current period relating to certain operating activities in the Company's consolidated statements of cash flows. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Given current credit markets, it is possible that the amounts recorded as derivative assets and liabilities could vary by material amounts prior to their settlement.
Accounting Pronouncements	In May 2014, the Financial Accounting Standards Board (or FASB) issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers (or ASU 2014-09). ASU 2014-09 will require an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This update creates a five-step model that requires entities to exercise judgment when considering the terms of the contract(s) which include (i) identifying the contract(s) with the customer, (ii) identifying the separate performance obligations in the contract, (iii) determining the transaction price, (iv) allocating the transaction price to the separate performance obligations, and (v) recognizing revenue as each performance obligation is satisfied. ASU 2014-09 is effective for the Company January 1, 2018 and will be applied as a cumulative-effect adjustment as of this date. The Company expects that the adoption of ASU 2014-09 may result in a change in the method of recognizing revenue for voyage charters, whereby the Company’s method of determining proportional performance will change from discharge-to-discharge to load-to-discharge. This would result in no revenue being recognized from discharge of the prior voyage to loading of the current voyage and all revenue being recognized from loading of the current voyage to discharge of the current voyage. In addition, the Company expects that the adoption of ASU 2014-09 may result in a change in the timing of the recognition of voyage expenses incurred during the period from discharge of the prior voyage to loading of the current voyage. The Company’s current policy is to expense such costs as incurred, and following adoption of ASU 2014-09 it is expected certain costs will be deferred and amortized over the load-to-discharge period. The Company expects that these principles will also be applied to voyage charters that are included in revenue sharing arrangements and, consequently, a portion of the Company’s monthly net revenue allocation from these revenue sharing arrangements would be deferred and recognized in future months. These changes would result in revenue and voyage expenses being recognized later than under the Company’s existing revenue and expense recognition policies, which may cause additional volatility in revenue and earnings between periods. ASC 2014-09 also changes the criteria to be used in determining whether the Company is operating as a principal or an agent in an arrangement. The Company expects that it will be considered to be the principal in certain crewing services it provides to other vessel owners and consequently the revenues earned and costs incurred will be presented on a gross basis compared with its current net presentation. The Company is in the final stages of completing its assessment of ASU 2014-09 and is focused on developing process changes, determining the transitional impact and completing other items required for the adoption of ASU 2014-09. In February 2016, the FASB issued Accounting Standards Update 2016-02, Leases (or ASU 2016-02). ASU 2016-02 establishes a right-of-use model that requires a lessee to record a right of use asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The Company expects to adopt ASU 2016-02 on January 1, 2018. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company expects that the adoption of ASU 2016-02 will result in a change in accounting method for the lease portion of the daily charter hire for the Company’s chartered-in vessels accounted for as operating leases and office leases with firm periods of greater than one year. Under ASU 2016-02, the Company will recognize a right-of-use asset and a lease liability on the balance sheet for these charters and office leases, whereas currently no right-of-use asset or lease liability is recognized. This will have the result of increasing the Company’s assets and liabilities. The pattern of expense recognition of chartered-in vessels and office leases is expected to remain substantially unchanged, unless the right-of-use asset becomes impaired. Based on lease agreements the Company has entered into on or prior to September 30, 2017, the increase to the Company’s assets and liabilities is expected to be less than $250 million. Such amount is preliminary and is subject to change based on the Company finalizing its methodology to divide contracts into their lease and non-lease components and finalizing the determination of the rate to discount future lease payments. The Company is in the final stages of completing its assessment of ASU 2016-02, and is focused on developing process changes, determining the transitional impact and completing other items required for the adoption of ASU 2016-02. In March 2016, the FASB issued Accounting Standards Update 2016-09, Improvements to Employee Share-Based Payment Accounting (or ASU 2016-09). ASU 2016-09 simplifies aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statements of cash flows. The Company adopted ASU 2016-09 on January 1, 2017 and the impact was immaterial. This new accounting guidance changed the presentation of cash payments for tax withholdings on share-settled equity awards from an operating cash outflow to financing cash outflow on the Company's statements of cash flows, and this change was applied retrospectively. In June 2016, the FASB issued Accounting Standards Update 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments. This update replaces the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. This update is effective for the Company on January 1, 2020, with a modified-retrospective approach. The Company is currently evaluating the effect of adopting this new guidance. In August 2016, the FASB issued Accounting Standards Update 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments, which, among other things, provides guidance on two acceptable approaches of classifying distributions received from equity method investees in the statements of cash flows. This update is effective for the Company on January 1, 2018, with a retrospective approach. The Company is currently evaluating the effect of adopting this new guidance. In November 2016, the FASB issued Accounting Standards Update 2016-18, Statement of Cash Flows: Restricted Cash (or ASU 2016-18). ASU 2016-18 requires that the statements of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Entities will also be required to reconcile such total to amounts on the balance sheet and disclose the nature of the restrictions. ASU 2016-18 is effective for the Company on January 1, 2018. Adoption of ASU 2016-18 will result in the Company’s statements of cash flows to be modified to include changes in restricted cash in addition to changes in cash and cash equivalents. In January 2017, the FASB issued Accounting Standards Update 2017-01, Clarifying the Definition of a Business, (or ASU 2017-01). ASU 2017-01 changes the definition of a business to assist entities with evaluating when a set of transferred assets and activities is a business. ASU 2017-01 requires an entity to evaluate if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets; if so, the set of transferred assets and activities is not a business. ASU 2017-01 also requires a business to include at least one substantive process and narrows the definition of outputs by more closely aligning it with how outputs are described in ASC 606. ASU 2017-01 is effective for annual reporting periods beginning after December 15, 2017, and for interim periods within those years. Early adoption is allowed and accounted for prospectively. If the adoption of ASU 2017-01 is completed prior to the closing of Teekay Tankers' merger with Tanker Investments Limited (or TIL) (see note 7c), this acquisition is expected to be accounted for as an asset acquisition, otherwise the acquisition is expected to be accounted for as a business combination. Unlike a business combination, no goodwill or bargain purchase gain is recognized as part of an asset acquisition, and transaction costs are not expensed. In August 2017, the FASB issued Accounting Standards Update 2017-12, Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities (or ASU 2017-12). ASU 2017-12 eliminates the requirement to separately measure and report hedge ineffectiveness and generally requires, for qualifying hedges, the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The guidance also modifies the accounting for components excluded from the assessment of hedge effectiveness, eases documentation and assessment requirements and modifies certain disclosure requirements. ASU 2017-12 will be effective for the Company January 1, 2019. The Company is currently evaluating the effect of adopting this new guidance.

In May 2014, the Financial Accounting Standards Board (or FASB) issued Accounting Standards Update 2014-09, Revenue from Contracts with Customers (or ASU 2014-09). ASU 2014-09 will require an entity to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This update creates a five-step model that requires entities to exercise judgment when considering the terms of the contract(s) which include (i) identifying the contract(s) with the customer, (ii) identifying the separate performance obligations in the contract, (iii) determining the transaction price, (iv) allocating the transaction price to the separate performance obligations, and (v) recognizing revenue as each performance obligation is satisfied. ASU 2014-09 is effective for the Company January 1, 2018 and will be applied as a cumulative-effect adjustment as of this date. The Company expects that the adoption of ASU 2014-09 may result in a change in the method of recognizing revenue for voyage charters, whereby the Company’s method of determining proportional performance will change from discharge-to-discharge to load-to-discharge. This would result in no revenue being recognized from discharge of the prior voyage to loading of the current voyage and all revenue being recognized from loading of the current voyage to discharge of the current voyage. In addition, the Company expects that the adoption of ASU 2014-09 may result in a change in the timing of the recognition of voyage expenses incurred during the period from discharge of the prior voyage to loading of the current voyage. The Company’s current policy is to expense such costs as incurred, and following adoption of ASU 2014-09 it is expected certain costs will be deferred and amortized over the load-to-discharge period. The Company expects that these principles will also be applied to voyage charters that are included in revenue sharing arrangements and, consequently, a portion of the Company’s monthly net revenue allocation from these revenue sharing arrangements would be deferred and recognized in future months. These changes would result in revenue and voyage expenses being recognized later than under the Company’s existing revenue and expense recognition policies, which may cause additional volatility in revenue and earnings between periods. ASC 2014-09 also changes the criteria to be used in determining whether the Company is operating as a principal or an agent in an arrangement. The Company expects that it will be considered to be the principal in certain crewing services it provides to other vessel owners and consequently the revenues earned and costs incurred will be presented on a gross basis compared with its current net presentation. The Company is in the final stages of completing its assessment of ASU 2014-09 and is focused on developing process changes, determining the transitional impact and completing other items required for the adoption of ASU 2014-09.

In February 2016, the FASB issued Accounting Standards Update 2016-02, Leases (or ASU 2016-02). ASU 2016-02 establishes a right-of-use model that requires a lessee to record a right of use asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The Company expects to adopt ASU 2016-02 on January 1, 2018. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company expects that the adoption of ASU 2016-02 will result in a change in accounting method for the lease portion of the daily charter hire for the Company’s chartered-in vessels accounted for as operating leases and office leases with firm periods of greater than one year. Under ASU 2016-02, the Company will recognize a right-of-use asset and a lease liability on the balance sheet for these charters and office leases, whereas currently no right-of-use asset or lease liability is recognized. This will have the result of increasing the Company’s assets and liabilities. The pattern of expense recognition of chartered-in vessels and office leases is expected to remain substantially unchanged, unless the right-of-use asset becomes impaired. Based on lease agreements the Company has entered into on or prior to September 30, 2017, the increase to the Company’s assets and liabilities is expected to be less than $250 million. Such amount is preliminary and is subject to change based on the Company finalizing its methodology to divide contracts into their lease and non-lease components and finalizing the determination of the rate to discount future lease payments. The Company is in the final stages of completing its assessment of ASU 2016-02, and is focused on developing process changes, determining the transitional impact and completing other items required for the adoption of ASU 2016-02.

In March 2016, the FASB issued Accounting Standards Update 2016-09, Improvements to Employee Share-Based Payment Accounting (or ASU 2016-09). ASU 2016-09 simplifies aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities and classification on the statements of cash flows. The Company adopted ASU 2016-09 on January 1, 2017 and the impact was immaterial. This new accounting guidance changed the presentation of cash payments for tax withholdings on share-settled equity awards from an operating cash outflow to financing cash outflow on the Company's statements of cash flows, and this change was applied retrospectively.

In June 2016, the FASB issued Accounting Standards Update 2016-13, Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments. This update replaces the incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. This update is effective for the Company on January 1, 2020, with a modified-retrospective approach. The Company is currently evaluating the effect of adopting this new guidance.

In August 2016, the FASB issued Accounting Standards Update 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments, which, among other things, provides guidance on two acceptable approaches of classifying distributions received from equity method investees in the statements of cash flows. This update is effective for the Company on January 1, 2018, with a retrospective approach. The Company is currently evaluating the effect of adopting this new guidance.

In November 2016, the FASB issued Accounting Standards Update 2016-18, Statement of Cash Flows: Restricted Cash (or ASU 2016-18). ASU 2016-18 requires that the statements of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Entities will also be required to reconcile such total to amounts on the balance sheet and disclose the nature of the restrictions. ASU 2016-18 is effective for the Company on January 1, 2018. Adoption of ASU 2016-18 will result in the Company’s statements of cash flows to be modified to include changes in restricted cash in addition to changes in cash and cash equivalents.

In January 2017, the FASB issued Accounting Standards Update 2017-01, Clarifying the Definition of a Business, (or ASU 2017-01). ASU 2017-01 changes the definition of a business to assist entities with evaluating when a set of transferred assets and activities is a business. ASU 2017-01 requires an entity to evaluate if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets; if so, the set of transferred assets and activities is not a business. ASU 2017-01 also requires a business to include at least one substantive process and narrows the definition of outputs by more closely aligning it with how outputs are described in ASC 606. ASU 2017-01 is effective for annual reporting periods beginning after December 15, 2017, and for interim periods within those years. Early adoption is allowed and accounted for prospectively. If the adoption of ASU 2017-01 is completed prior to the closing of Teekay Tankers' merger with Tanker Investments Limited (or TIL) (see note 7c), this acquisition is expected to be accounted for as an asset acquisition, otherwise the acquisition is expected to be accounted for as a business combination. Unlike a business combination, no goodwill or bargain purchase gain is recognized as part of an asset acquisition, and transaction costs are not expensed.

In August 2017, the FASB issued Accounting Standards Update 2017-12, Derivatives and Hedging - Targeted Improvements to Accounting for Hedging Activities (or ASU 2017-12). ASU 2017-12 eliminates the requirement to separately measure and report hedge ineffectiveness and generally requires, for qualifying hedges, the entire change in the fair value of a hedging instrument to be presented in the same income statement line as the hedged item. The guidance also modifies the accounting for components excluded from the assessment of hedge effectiveness, eases documentation and assessment requirements and modifies certain disclosure requirements. ASU 2017-12 will be effective for the Company January 1, 2019. The Company is currently evaluating the effect of adopting this new guidance.