Summary of Significant Accounting Policies	9 Months Ended
Sep. 30, 2011
Significant 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 of December 31, 2010 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, 2010. 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, the valuation of equity investments, sales deductions, income taxes (including provisions for uncertain tax positions and the realization of deferred tax assets), provisions for litigation and legal proceedings, and contingent consideration receivable from product divestments. 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 Revenue Recognition in Multiple Deliverable Revenue Arrangements On January 1, 2011 the Company adopted new guidance issued by the Financial Accounting Standard Board (“FASB”) on revenue recognition in multiple deliverable revenue arrangements. This amends the existing guidance on allocating consideration received between the elements in a multiple-deliverable arrangement and establishes a selling price hierarchy for determining the selling price of a deliverable. The selling price used for each deliverable will be based on vendor specific objective evidence (“VSOE”) if available, third party evidence if VSOE is not available, or estimated selling price if neither VSOE nor third party evidence is available. It replaces the term “fair value” in the revenue allocation with “selling price” to clarify that the allocation of revenue is based on entity specific assumptions rather than the assumptions of a market place participant. The guidance eliminates the residual method of allocation and requires that arrangement consideration be allocated using the relative selling price method. The guidance also significantly expands the disclosures related to a vendor's multiple-deliverable revenue arrangements. The guidance has been adopted prospectively from January 1, 2011 for new arrangements, or existing arrangements which have been materially modified subsequent to the date of adoption. The adoption of the guidance did not impact the Company's consolidated financial position, results of operations or cash flows. Effect of Denominating the Exercise Price of a Share-Based Payment Award in the Currency of the Market in Which the Underlying Equity Security Trades On January 1, 2011 the Company adopted new guidance issued by the FASB on the effect of denominating the exercise price of a share-based payment award in the currency of the market in which the underlying equity security trades. This guidance clarifies that an employee share-based payment award with an exercise price denominated in the currency of a market in which a substantial portion of the entity's equity securities trades should not be considered to contain a condition that is not a market, performance, or service condition. Therefore, an entity would not classify such an award as a liability if it otherwise qualifies as equity. The Company has historically accounted for share based payment awards in a manner consistent with the guidance, and therefore the adoption of this guidance did not impact the Company's consolidated financial position, results of operations or cash flows. Milestone Method of Revenue Recognition On January 1, 2011 the Company adopted new guidance issued by the FASB on defining a milestone and determining when it may be appropriate to apply the milestone method of revenue recognition for research or development transactions. This guidance clarifies that: (i) consideration that is contingent on achievement of a milestone in its entirety may be recognized as revenue in the period in which the milestone is achieved only if the milestone is judged to meet certain criteria to be considered substantive; (ii) milestones should be considered substantive in their entirety and may not be bifurcated; (iii) an arrangement may contain both substantive and non substantive milestones; and (iv) each milestone should be evaluated individually to determine if it is substantive. The adoption of the guidance did not impact the Company's consolidated financial position, results of operations or cash flows. Fees Paid to Federal Government by Pharmaceutical Manufacturers On January 1, 2011 the Company adopted new guidance issued by the FASB on the accounting for the annual fee paid by pharmaceutical manufacturers to the US Treasury in accordance with the Patient Protection and Affordable Care Act as amended by the Health Care and Education Reconciliation Act for each calendar year beginning on or after January 1, 2011. The annual fee in 2011 is $2.5 billion. A portion of the fee will be allocated to individual entities on the basis of the amount of their branded prescription drug sales to certain US Government programs for the preceding year as a percentage of the industry's branded prescription drug sales for the same period to these same programs. This guidance specifies that the liability for the fee should be estimated and recorded in full upon the first qualifying sale with a corresponding deferred cost that is amortized to expense using a straight-line method of allocation unless another method better allocates the fee over the calendar year that it is payable. The adoption of the guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows. Disclosure of Supplementary Pro Forma Information for Business Combinations On January 1, 2011 the Company adopted new guidance issued by the FASB which clarifies the acquisition date that should be used for reporting pro forma financial information disclosures in a business combination when comparative financial statements are presented. The guidance specifies that the entity should disclose revenue and earnings of the combined entity as though the business combination that occurred during the current year had occurred as of the beginning of the comparable prior annual reporting period. The guidance also improves the usefulness of the pro forma revenue and earnings disclosures by requiring a description of the nature and amount of material, nonrecurring pro forma adjustments that are directly attributable to the business combination. The guidance is effective prospectively for business combinations for which the acquisition date is on or after January 1, 2011. The Company has historically presented proforma business combination disclosures in accordance with the guidance, and therefore the adoption of guidance did not impact the Company's disclosure on business combinations. To be adopted in future periods Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in US GAAP and International Financial Reporting standards (“IFRS”) In May 2011 the FASB issued guidance on fair value measurement and disclosure, which both amends existing requirements and improves the comparability of fair value measurement and disclosure between US GAAP and IFRS. Some of the amendments clarify the application of existing fair value measurement requirements and other amendments change a particular principle or requirement for measuring fair value or for disclosing information about fair value measurements. The guidance will be effective prospectively for interim and annual periods beginning after December 15, 2011. Early adoption is not permitted. The Company is currently evaluating the impact of adopting this guidance. Presentation of Comprehensive Income In June 2011 the FASB issued guidance on the presentation of comprehensive income which revises the manner in which entities present comprehensive income in their financial statements. The guidance requires entities to report components of comprehensive income in either: (i) a single, continuous statement of comprehensive income; or (ii) two separate but consecutive statements. The guidance does not change those items which must be reported in other comprehensive income, and does not change the definition of net income or the calculation of earnings per share. The guidance will be effective retrospectively for interim and annual periods beginning after December 15, 2011. Early adoption is permitted. The Company is currently evaluating the impact of adopting this guidance. Goodwill Impairment Testing In September 2011 the FASB issued guidance on the testing of goodwill for impairment. The guidance permits an entity to first assess the qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, an entity determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. The more-likely-than-not threshold is defined as having a likelihood of more than 50 percent. An entity also has the option to bypass the qualitative assessment for any reporting unit in any period and proceed directly to performing the first step of the two-step goodwill impairment test and may resume performing the qualitative assessment in any subsequent periods. The guidance will be effective for interim and annual goodwill impairment tests performed for fiscal years beginning after December 15, 2011. Early adoption is permitted. The Company is currently evaluating the impact of adopting this guidance.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2011

Significant 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 of December 31, 2010 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, 2010.

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, the valuation of equity investments, sales deductions, income taxes (including provisions for uncertain tax positions and the realization of deferred tax assets), provisions for litigation and legal proceedings, and contingent consideration receivable from product divestments. 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

Revenue Recognition in Multiple Deliverable Revenue Arrangements

On January 1, 2011 the Company adopted new guidance issued by the Financial Accounting Standard Board (“FASB”) on revenue recognition in multiple deliverable revenue arrangements. This amends the existing guidance on allocating consideration received between the elements in a multiple-deliverable arrangement and establishes a selling price hierarchy for determining the selling price of a deliverable. The selling price used for each deliverable will be based on vendor specific objective evidence (“VSOE”) if available, third party evidence if VSOE is not available, or estimated selling price if neither VSOE nor third party evidence is available. It replaces the term “fair value” in the revenue allocation with “selling price” to clarify that the allocation of revenue is based on entity specific assumptions rather than the assumptions of a market place participant. The guidance eliminates the residual method of allocation and requires that arrangement consideration be allocated using the relative selling price method. The guidance also significantly expands the disclosures related to a vendor's multiple-deliverable revenue arrangements. The guidance has been adopted prospectively from January 1, 2011 for new arrangements, or existing arrangements which have been materially modified subsequent to the date of adoption. The adoption of the guidance did not impact the Company's consolidated financial position, results of operations or cash flows.

Effect of Denominating the Exercise Price of a Share-Based Payment Award in the Currency of the Market in Which the Underlying Equity Security Trades

On January 1, 2011 the Company adopted new guidance issued by the FASB on the effect of denominating the exercise price of a share-based payment award in the currency of the market in which the underlying equity security trades. This guidance clarifies that an employee share-based payment award with an exercise price denominated in the currency of a market in which a substantial portion of the entity's equity securities trades should not be considered to contain a condition that is not a market, performance, or service condition. Therefore, an entity would not classify such an award as a liability if it otherwise qualifies as equity. The Company has historically accounted for share based payment awards in a manner consistent with the guidance, and therefore the adoption of this guidance did not impact the Company's consolidated financial position, results of operations or cash flows.

Milestone Method of Revenue Recognition

On January 1, 2011 the Company adopted new guidance issued by the FASB on defining a milestone and determining when it may be appropriate to apply the milestone method of revenue recognition for research or development transactions. This guidance clarifies that: (i) consideration that is contingent on achievement of a milestone in its entirety may be recognized as revenue in the period in which the milestone is achieved only if the milestone is judged to meet certain criteria to be considered substantive; (ii) milestones should be considered substantive in their entirety and may not be bifurcated; (iii) an arrangement may contain both substantive and non substantive milestones; and (iv) each milestone should be evaluated individually to determine if it is substantive. The adoption of the guidance did not impact the Company's consolidated financial position, results of operations or cash flows.

Fees Paid to Federal Government by Pharmaceutical Manufacturers

On January 1, 2011 the Company adopted new guidance issued by the FASB on the accounting for the annual fee paid by pharmaceutical manufacturers to the US Treasury in accordance with the Patient Protection and Affordable Care Act as amended by the Health Care and Education Reconciliation Act for each calendar year beginning on or after January 1, 2011. The annual fee in 2011 is $2.5 billion. A portion of the fee will be allocated to individual entities on the basis of the amount of their branded prescription drug sales to certain US Government programs for the preceding year as a percentage of the industry's branded prescription drug sales for the same period to these same programs. This guidance specifies that the liability for the fee should be estimated and recorded in full upon the first qualifying sale with a corresponding deferred cost that is amortized to expense using a straight-line method of allocation unless another method better allocates the fee over the calendar year that it is payable. The adoption of the guidance did not have a material impact on the Company's consolidated financial position, results of operations or cash flows.

Disclosure of Supplementary Pro Forma Information for Business Combinations

On January 1, 2011 the Company adopted new guidance issued by the FASB which clarifies the acquisition date that should be used for reporting pro forma financial information disclosures in a business combination when comparative financial statements are presented. The guidance specifies that the entity should disclose revenue and earnings of the combined entity as though the business combination that occurred during the current year had occurred as of the beginning of the comparable prior annual reporting period. The guidance also improves the usefulness of the pro forma revenue and earnings disclosures by requiring a description of the nature and amount of material, nonrecurring pro forma adjustments that are directly attributable to the business combination. The guidance is effective prospectively for business combinations for which the acquisition date is on or after January 1, 2011. The Company has historically presented proforma business combination disclosures in accordance with the guidance, and therefore the adoption of guidance did not impact the Company's disclosure on business combinations.

To be adopted in future periods

Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in US GAAP and International Financial Reporting standards (“IFRS”)

In May 2011 the FASB issued guidance on fair value measurement and disclosure, which both amends existing requirements and improves the comparability of fair value measurement and disclosure between US GAAP and IFRS. Some of the amendments clarify the application of existing fair value measurement requirements and other amendments change a particular principle or requirement for measuring fair value or for disclosing information about fair value measurements. The guidance will be effective prospectively for interim and annual periods beginning after December 15, 2011. Early adoption is not permitted. The Company is currently evaluating the impact of adopting this guidance.

Presentation of Comprehensive Income

In June 2011 the FASB issued guidance on the presentation of comprehensive income which revises the manner in which entities present comprehensive income in their financial statements. The guidance requires entities to report components of comprehensive income in either: (i) a single, continuous statement of comprehensive income; or (ii) two separate but consecutive statements. The guidance does not change those items which must be reported in other comprehensive income, and does not change the definition of net income or the calculation of earnings per share. The guidance will be effective retrospectively for interim and annual periods beginning after December 15, 2011. Early adoption is permitted. The Company is currently evaluating the impact of adopting this guidance.

Goodwill Impairment Testing

In September 2011 the FASB issued guidance on the testing of goodwill for impairment. The guidance permits an entity to first assess the qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, an entity determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. The more-likely-than-not threshold is defined as having a likelihood of more than 50 percent. An entity also has the option to bypass the qualitative assessment for any reporting unit in any period and proceed directly to performing the first step of the two-step goodwill impairment test and may resume performing the qualitative assessment in any subsequent periods. The guidance will be effective for interim and annual goodwill impairment tests performed for fiscal years beginning after December 15, 2011. Early adoption is permitted. The Company is currently evaluating the impact of adopting this guidance.