Accounting Pronouncements	9 Months Ended
Sep. 30, 2017
Accounting Changes and Error Corrections [Abstract]
Accounting Pronouncements	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.

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.