Long-term Debt	12 Months Ended
Dec. 31, 2011
Long-term Debt, Unclassified [Abstract]
Long-term Debt Disclosure	17. Long-term debt Revolving Credit Facilities Agreement On November 23, 2010 the Company entered into a committed multicurrency revolving and swingline facilities agreement with a number of financial institutions, for which Abbey National Treasury Services Plc (trading as Santander Global Banking and Markets), Bank of America Securities Limited, Barclays Capital, Citigroup Global Markets Limited, Lloyds TSB Bank plc and The Royal Bank of Scotland plc acted as mandated lead arrangers and bookrunners (the “new RCF”). The new RCF is for an aggregate amount of $1,200 million and cancelled the Company's existing committed revolving credit facility (the “old RCF”). The new RCF, which includes a $250 million swingline facility, may be used for general corporate purposes and matures on November 23, 2015. The interest rate on each loan drawn under the new RCF for each interest period is the percentage rate per annum which is the aggregate of the applicable margin (ranging from 0.90 to 2.25 per cent per annum) and LIBOR for the applicable currency and interest period. Shire also pays a commitment fee on undrawn amounts at 35 per cent per annum of the applicable margin. Under the new RCF it is required that (i) Shire's ratio of Net Debt to EBITDA (as defined within the new RCF agreement) does not exceed 3.5 to 1 for either the 12 month period ending December 31 or June 30 unless Shire has exercised its option (which is subject to certain conditions) to increase it to 4.0 to 1 for two consecutive testing dates; (ii) the ratio of EBITDA to Net Interest (as defined in the new RCF agreement) must not be less than 4.0 to 1, for either the 12 month period ending December 31 or June 30, and (iii) additional limitations on the creation of liens, disposal of assets, incurrence of indebtedness, making of loans, giving of guarantees and granting security over assets. These financial and operating covenants have not had, and are not expected to have, an effect on the Company's financial position and liquidity. On entering into the new RCF in November 2010 the Company paid arrangement costs of $8.0 million, which have been recorded as deferred charges and amortized over the contractual term of the new RCF. The availability of loans under the new RCF is subject to customary conditions. Other long term debt During 2007 and 2009 Shire entered into certain multi-year leases for its HGT business unit at North Reading and Lexington, Massachusetts. For some of these leases Shire was considered the in substance owner of the related properties over their construction period and as a result Shire recorded assets (being the fair value of the building element at inception of the relevant lease) within property, plant and equipment and the corresponding building financing obligations were recorded within other long term debt. The land element of these leases was accounted for as an operating lease. In the year to December 31, 2009, on entering into certain of these leases Shire extended the term of the existing leases at Lexington Technology Park. This lease extension was accounted for as a substantial modification of the existing building finance obligation, whereby the existing liability was derecognized and a building financing obligation based on the fair value of the liability under the revised lease terms recorded in its place. The substantial modification resulted in a non-cash gain of $5.7 million in the year to December 31, 2009 which was recorded to other (expense)/income, net. On June 30, 2010, as outlined in Note 11, Shire completed the purchase of certain properties on the Lexington Technology Park campus, including the properties held under building finance obligations. Accordingly Shire applied $43.1 million of the purchase price for the Lexington campus to extinguish the existing building finance obligations, recognizing a loss of $3.6 million within other (expense)/income, net in the year to December 31, 2010.

Long-term Debt

12 Months Ended

Dec. 31, 2011

Long-term Debt, Unclassified [Abstract]

17. Long-term debt

Revolving Credit Facilities Agreement

On November 23, 2010 the Company entered into a committed multicurrency revolving and swingline facilities agreement with a number of financial institutions, for which Abbey National Treasury Services Plc (trading as Santander Global Banking and Markets), Bank of America Securities Limited, Barclays Capital, Citigroup Global Markets Limited, Lloyds TSB Bank plc and The Royal Bank of Scotland plc acted as mandated lead arrangers and bookrunners (the “new RCF”). The new RCF is for an aggregate amount of $1,200 million and cancelled the Company's existing committed revolving credit facility (the “old RCF”). The new RCF, which includes a $250 million swingline facility, may be used for general corporate purposes and matures on November 23, 2015.

The interest rate on each loan drawn under the new RCF for each interest period is the percentage rate per annum which is the aggregate of the applicable margin (ranging from 0.90 to 2.25 per cent per annum) and LIBOR for the applicable currency and interest period. Shire also pays a commitment fee on undrawn amounts at 35 per cent per annum of the applicable margin.

Under the new RCF it is required that (i) Shire's ratio of Net Debt to EBITDA (as defined within the new RCF agreement) does not exceed 3.5 to 1 for either the 12 month period ending December 31 or June 30 unless Shire has exercised its option (which is subject to certain conditions) to increase it to 4.0 to 1 for two consecutive testing dates; (ii) the ratio of EBITDA to Net Interest (as defined in the new RCF agreement) must not be less than 4.0 to 1, for either the 12 month period ending December 31 or June 30, and (iii) additional limitations on the creation of liens, disposal of assets, incurrence of indebtedness, making of loans, giving of guarantees and granting security over assets. These financial and operating covenants have not had, and are not expected to have, an effect on the Company's financial position and liquidity.

On entering into the new RCF in November 2010 the Company paid arrangement costs of $8.0 million, which have been recorded as deferred charges and amortized over the contractual term of the new RCF.

The availability of loans under the new RCF is subject to customary conditions.

Other long term debt

During 2007 and 2009 Shire entered into certain multi-year leases for its HGT business unit at North Reading and Lexington, Massachusetts. For some of these leases Shire was considered the in substance owner of the related properties over their construction period and as a result Shire recorded assets (being the fair value of the building element at inception of the relevant lease) within property, plant and equipment and the corresponding building financing obligations were recorded within other long term debt. The land element of these leases was accounted for as an operating lease.

In the year to December 31, 2009, on entering into certain of these leases Shire extended the term of the existing leases at Lexington Technology Park. This lease extension was accounted for as a substantial modification of the existing building finance obligation, whereby the existing liability was derecognized and a building financing obligation based on the fair value of the liability under the revised lease terms recorded in its place. The substantial modification resulted in a non-cash gain of $5.7 million in the year to December 31, 2009 which was recorded to other (expense)/income, net.

On June 30, 2010, as outlined in Note 11, Shire completed the purchase of certain properties on the Lexington Technology Park campus, including the properties held under building finance obligations. Accordingly Shire applied $43.1 million of the purchase price for the Lexington campus to extinguish the existing building finance obligations, recognizing a loss of $3.6 million within other (expense)/income, net in the year to December 31, 2010.