Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. Summary of Significant Accounting Policies (a) Basis of preparation These interim financial statements of Shire plc and its subsidiaries (collectively “Shire” or the “Company”) and other financial information included in this Form 10-Q, are unaudited. They have been prepared in accordance with generally accepted accounting principles in the United States of America (“US GAAP”) and US Securities and Exchange Commission (“SEC”) regulations for interim reporting. The balance sheet as at December 31, 2014 was derived from audited financial statements but does not include all disclosures required by US GAAP. These interim financial statements should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company's Annual Report on Form 10-K for the year to December 31, 2014. Certain information and footnote disclosures normally included in financial statements prepared in accordance with US GAAP have been condensed or omitted from these interim financial statements. However, these interim financial statements include all adjustments, which are, in the opinion of management, necessary to fairly state the results of the interim period and the Company believes that the disclosures are adequate to make the information presented not misleading. Interim results are not necessarily indicative of results to be expected for the full year. (b) Use of estimates in interim financial statements The preparation of interim financial statements, in conformity with US GAAP and SEC regulations, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenues and expenses during the reporting period. Estimates and assumptions are primarily made in relation to the valuation of intangible assets, sales deductions, income taxes (including provisions for uncertain tax positions and the realization of deferred tax assets), provisions for litigation and legal proceedings, contingent consideration receivable from product divestments and contingent consideration payable in respect of business combinations and asset purchases. If actual results differ from the Company's estimates, or to the extent these estimates are adjusted in future periods, the Company's results of operations could either benefit from, or be adversely affected by, any such change in estimate. (c) New accounting pronouncements Adopted during the period Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity In April 2014 the Financial Accounting Standard Board (“FASB”) issued guidance on the reporting of discontinued operations and disclosures of disposals of components of an entity. The amendments in this update revise the definition of discontinued operations by limiting discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have (or will have) a major effect on an entity's operations and financial results. The guidance requires expanded disclosures for discontinued operations which provide users of financial statements with more information about the assets, liabilities, revenues, and expenses of discontinued operations. The guidance also requires an entity to disclose the pre-tax profit or loss of an individually significant component of an entity that does not qualify for discontinued operations reporting. Shire adopted this guidance in the period, which will be effective for discontinued operations occurring after January 1, 2015. The adoption of this guidance did not impact the Company's consolidated financial position, results of operations or cash flows. To be adopted in future periods Revenue from Contracts with Customers In May 2014 the FASB and the International Accounting Standards Board (together the “Accounting Standards Boards”) issued a new accounting standard that is intended to clarify and converge the financial reporting requirements for revenue from contracts with customers. The core principle of the standard is that an “entity recognizes revenue to depict the transfer of 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”. To achieve that core principle the Accounting Standard Boards developed a five-step model (as presented below) and related application guidance, which will replace most existing revenue recognition guidance in US GAAP. Five-step model: Step 1: Identify the contract(s) with a customer. Step 2: Identify the performance obligations in the contract. Step 3: Determine the transaction price. Step 4: Allocate the transaction price to the performance obligations in the contract. Step 5: Recognize revenue when (or as) the entity satisfies a performance obligation. The Accounting Standards Boards also issued new qualitative and quantitative disclosure requirements as part of the new accounting standard which aims to enable financial statement users to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. In April 2015 the FASB proposed to defer the effective date of the guidance by one year. Based on this proposal, public entities would need to apply the new guidance for annual reporting periods beginning after December 15, 2017, and interim periods therein. The Company is currently evaluating the impact of adopting this guidance. Elimination of Certain Financial Reporting Requirements, Including an Amendment to Variable Interest Entities (“VIEs”) Guidance in Topic 810, Consolidation In June 2014 the FASB issued guidance on the reporting requirements for development stage entities. The amendments in this update simplify the existing guidance by removing all incremental financial reporting requirements for development stage entities. The amendments also eliminate an exception provided with respect to development stage entities in Topic 810, Consolidation, for determining whether an entity is a VIE on the basis of the amount of equity that is at risk. The elimination of the exception may change the consolidation analysis, consolidation decision, and disclosure requirements for a reporting entity that has an interest in an entity in the development stage. The guidance to eliminate the exception to the sufficiency-of-equity-at-risk criterion for development stage entities should be applied retrospectively for annual reporting periods beginning after December 15, 2015, and interim periods therein. Early application of both of these amendments is permitted for any annual reporting period or interim period for which the entity's financial statements have not yet been issued. The Company is currently evaluating the impact of adopting this guidance. Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern In August 2014 the FASB issued guidance about management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. An entity's management should evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity's ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the date that the financial statements are available to be issued when applicable). Management's evaluation should be based on relevant conditions and events that are known and reasonably knowable at the date that the financial statements are issued (or available to be issued). Substantial doubt about an entity's ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity will be unable to meet its obligations as they become due within one year after the date that the financial statements are issued (or available to be issued). The term probable is used consistently with its use in Topic 450, Contingencies. The amendments in this update are effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial position, results of operations and cash flows. Amendments to the Consolidation Analysis In February 2015 the FASB issued guidance to respond to stakeholders' concerns about the current accounting for consolidation of certain legal entities. Financial statement users asserted that in certain situations in which consolidation is ultimately required, deconsolidated financial statements are necessary to better analyze the reporting entity's economic and operational results. Previously, the FASB issued an indefinite deferral for certain entities to partially address those concerns. However, the amendments in this guidance rescind that deferral and address those concerns by making changes to the consolidation guidance. Under the amendments, all reporting entities are within the scope of Subtopic 810-10, Consolidation, including limited partnerships and similar legal entities, unless a scope exception applies. The presumption that a general partner controls a limited partnership has been eliminated. In addition, fees paid to decision makers that meet certain conditions no longer cause decision makers to consolidate a VIE in certain instances. The amendments place more emphasis in the consolidation evaluation on variable interests other than fee arrangements such as principal investment risk (for example, debt or equity interests), guarantees of the value of the assets or liabilities of the VIE, written put options on the assets of the VIE, or similar obligations, including some liquidity commitments or agreements (explicit or implicit). Additionally, the amendments reduce the extent to which related party arrangements cause an entity to be considered a primary beneficiary. The amendments are effective for public business entities for fiscal years, and for interim periods therein, beginning after December 15, 2015. Early adoption is permitted, including adoption in an interim period. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial position, results of operations and cash flows. Simplifying the Presentation of Debt Issuance Costs In April 2015 the FASB issued guidance to simplify the presentation of debt issuance costs. The guidance requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this update. The amendments in this update are effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods therein. Early adoption of the amendments in this update is permitted for financial statements that have not been previously issued. An entity should apply the new guidance on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. Upon transition, an entity is required to comply with the applicable disclosures for a change in an accounting principle. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial position, results of operations and cash flows.

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2015

Summary of Significant Accounting Policies

1. Summary of Significant Accounting Policies

(a) Basis of preparation

These interim financial statements of Shire plc and its subsidiaries (collectively “Shire” or the “Company”) and other financial information included in this Form 10-Q, are unaudited. They have been prepared in accordance with generally accepted accounting principles in the United States of America (“US GAAP”) and US Securities and Exchange Commission (“SEC”) regulations for interim reporting.

The balance sheet as at December 31, 2014 was derived from audited financial statements but does not include all disclosures required by US GAAP.

These interim financial statements should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company's Annual Report on Form 10-K for the year to December 31, 2014.

Certain information and footnote disclosures normally included in financial statements prepared in accordance with US GAAP have been condensed or omitted from these interim financial statements. However, these interim financial statements include all adjustments, which are, in the opinion of management, necessary to fairly state the results of the interim period and the Company believes that the disclosures are adequate to make the information presented not misleading. Interim results are not necessarily indicative of results to be expected for the full year.

(b) Use of estimates in interim financial statements

The preparation of interim financial statements, in conformity with US GAAP and SEC regulations, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenues and expenses during the reporting period. Estimates and assumptions are primarily made in relation to the valuation of intangible assets, sales deductions, income taxes (including provisions for uncertain tax positions and the realization of deferred tax assets), provisions for litigation and legal proceedings, contingent consideration receivable from product divestments and contingent consideration payable in respect of business combinations and asset purchases. If actual results differ from the Company's estimates, or to the extent these estimates are adjusted in future periods, the Company's results of operations could either benefit from, or be adversely affected by, any such change in estimate.

Adopted during the period

Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity

In April 2014 the Financial Accounting Standard Board (“FASB”) issued guidance on the reporting of discontinued operations and disclosures of disposals of components of an entity. The amendments in this update revise the definition of discontinued operations by limiting discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have (or will have) a major effect on an entity's operations and financial results. The guidance requires expanded disclosures for discontinued operations which provide users of financial statements with more information about the assets, liabilities, revenues, and expenses of discontinued operations. The guidance also requires an entity to disclose the pre-tax profit or loss of an individually significant component of an entity that does not qualify for discontinued operations reporting.

Shire adopted this guidance in the period, which will be effective for discontinued operations occurring after January 1, 2015. The adoption of this guidance did not impact the Company's consolidated financial position, results of operations or cash flows.

To be adopted in future periods

Revenue from Contracts with Customers

In May 2014 the FASB and the International Accounting Standards Board (together the “Accounting Standards Boards”) issued a new accounting standard that is intended to clarify and converge the financial reporting requirements for revenue from contracts with customers. The core principle of the standard is that an “entity recognizes revenue to depict the transfer of 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”. To achieve that core principle the Accounting Standard Boards developed a five-step model (as presented below) and related application guidance, which will replace most existing revenue recognition guidance in US GAAP.

Five-step model:

Step 1: Identify the contract(s) with a customer.

Step 2: Identify the performance obligations in the contract.

Step 3: Determine the transaction price.

Step 4: Allocate the transaction price to the performance obligations in the contract.

Step 5: Recognize revenue when (or as) the entity satisfies a performance obligation.

The Accounting Standards Boards also issued new qualitative and quantitative disclosure requirements as part of the new accounting standard which aims to enable financial statement users to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers.

In April 2015 the FASB proposed to defer the effective date of the guidance by one year. Based on this proposal, public entities would need to apply the new guidance for annual reporting periods beginning after December 15, 2017, and interim periods therein. The Company is currently evaluating the impact of adopting this guidance.

Elimination of Certain Financial Reporting Requirements, Including an Amendment to Variable Interest Entities (“VIEs”) Guidance in Topic 810, Consolidation

In June 2014 the FASB issued guidance on the reporting requirements for development stage entities. The amendments in this update simplify the existing guidance by removing all incremental financial reporting requirements for development stage entities. The amendments also eliminate an exception provided with respect to development stage entities in Topic 810, Consolidation, for determining whether an entity is a VIE on the basis of the amount of equity that is at risk. The elimination of the exception may change the consolidation analysis, consolidation decision, and disclosure requirements for a reporting entity that has an interest in an entity in the development stage. The guidance to eliminate the exception to the sufficiency-of-equity-at-risk criterion for development stage entities should be applied retrospectively for annual reporting periods beginning after December 15, 2015, and interim periods therein. Early application of both of these amendments is permitted for any annual reporting period or interim period for which the entity's financial statements have not yet been issued. The Company is currently evaluating the impact of adopting this guidance.

Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern

In August 2014 the FASB issued guidance about management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. An entity's management should evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity's ability to continue as a going concern within one year after the date that the financial statements are issued (or within one year after the date that the financial statements are available to be issued when applicable). Management's evaluation should be based on relevant conditions and events that are known and reasonably knowable at the date that the financial statements are issued (or available to be issued). Substantial doubt about an entity's ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity will be unable to meet its obligations as they become due within one year after the date that the financial statements are issued (or available to be issued). The term probable is used consistently with its use in Topic 450, Contingencies. The amendments in this update are effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early application is permitted. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial position, results of operations and cash flows.

Amendments to the Consolidation Analysis

In February 2015 the FASB issued guidance to respond to stakeholders' concerns about the current accounting for consolidation of certain legal entities. Financial statement users asserted that in certain situations in which consolidation is ultimately required, deconsolidated financial statements are necessary to better analyze the reporting entity's economic and operational results. Previously, the FASB issued an indefinite deferral for certain entities to partially address those concerns. However, the amendments in this guidance rescind that deferral and address those concerns by making changes to the consolidation guidance.

Under the amendments, all reporting entities are within the scope of Subtopic 810-10, Consolidation, including limited partnerships and similar legal entities, unless a scope exception applies. The presumption that a general partner controls a limited partnership has been eliminated. In addition, fees paid to decision makers that meet certain conditions no longer cause decision makers to consolidate a VIE in certain instances. The amendments place more emphasis in the consolidation evaluation on variable interests other than fee arrangements such as principal investment risk (for example, debt or equity interests), guarantees of the value of the assets or liabilities of the VIE, written put options on the assets of the VIE, or similar obligations, including some liquidity commitments or agreements (explicit or implicit). Additionally, the amendments reduce the extent to which related party arrangements cause an entity to be considered a primary beneficiary.

The amendments are effective for public business entities for fiscal years, and for interim periods therein, beginning after December 15, 2015. Early adoption is permitted, including adoption in an interim period. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial position, results of operations and cash flows.

Simplifying the Presentation of Debt Issuance Costs

In April 2015 the FASB issued guidance to simplify the presentation of debt issuance costs. The guidance requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this update. The amendments in this update are effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods therein.

Early adoption of the amendments in this update is permitted for financial statements that have not been previously issued. An entity should apply the new guidance on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. Upon transition, an entity is required to comply with the applicable disclosures for a change in an accounting principle. The Company does not expect the adoption of this guidance to have a material effect on its consolidated financial position, results of operations and cash flows.