Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2014
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, 2013 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, 2013. 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 To be adopted in future periods 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. The guidance will be effective for disposals (or classifications as held for sale) of components of an entity that occur within annual periods beginning on or after December 15, 2014, and interim periods within annual periods beginning on or after December 15, 2015. Early adoption is permitted, but only for disposals (or classifications as held for sale) that have not been reported in financial statements previously issued or available for issuance. 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, 2014

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, 2013 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, 2013.

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.

To be adopted in future periods

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.

The guidance will be effective for disposals (or classifications as held for sale) of components of an entity that occur within annual periods beginning on or after December 15, 2014, and interim periods within annual periods beginning on or after December 15, 2015. Early adoption is permitted, but only for disposals (or classifications as held for sale) that have not been reported in financial statements previously issued or available for issuance. 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.