Convertible Bonds	12 Months Ended
Dec. 31, 2011
Convertible Debt [Abstract]
Convertible Bonds Disclosure	15. Convertible Bonds Shire 2.75% Convertible Bonds due 2014 On May 9, 2007 Shire issued $1,100 million in principal amount of 2.75% convertible bonds due 2014 and convertible into fully paid ordinary shares of Shire plc (the “Bonds”). The net proceeds of issuing the Bonds, after deducting the commissions and other direct costs of issue, totaled $1,081.7 million. In connection with the Scheme the Trust Deed was amended and restated in 2008 in order to provide that, following the substitution of Shire plc in place of Old Shire as the principal obligor and issuer of the Convertible Bonds, the Bonds would be convertible into ordinary shares of Shire plc. The Bonds were issued at 100% of their principal amount, and unless previously purchased and cancelled, redeemed or converted, will be redeemed on May 9, 2014 (the “Final Maturity Date”) at their principal amount. The Bonds bear interest at 2.75% per annum, payable semi-annually in arrears on November 9 and May 9. The Bonds constitute direct, unconditional, unsubordinated and unsecured obligations of the Company, and rank pari passu and ratably, without any preference amongst themselves, and equally with all other existing and future unsecured and unsubordinated obligations of the Company. The Bonds may be redeemed at the option of the Company, at their principal amount together with accrued and unpaid interest if: (i) at any time after May 23, 2012 if on no less than 20 dealing days in any period of 30 consecutive dealing days the value of Shire's ordinary shares underlying each Bond in the principal amount of $100,000 would exceed $130,000; or (ii) at any time conversion rights have been exercised, and/or purchases and corresponding cancellations, and/or redemptions effected in respect of 85% or more in principal amount of Bonds originally issued. The Bonds may also be redeemed at the option of the Bond holder at their principal amount including accrued but unpaid interest on May 9, 2012 (the “Put Option”), or following the occurrence of a change of control of Shire. The Bonds are repayable in US dollars, but also contain provisions entitling the Company to settle redemption amounts in Pounds sterling, or in the case of the Final Maturity Date and following exercise of the Put Option, by delivery of the underlying ordinary shares and a cash top-up amount. In accordance with US GAAP, as the exercise of the Put Option could require the Company to redeem the Bonds within twelve months of the balance sheet date, the Bonds have been presented as a current liability at December 31, 2011. The Bonds are convertible into ordinary shares during the conversion period, being the period from June 18, 2007 until the earlier of: (i) the close of business on the date falling fourteen days prior to the Final Maturity Date; (ii) if the Bonds have been called for redemption by the Company, the close of business fourteen days before the date fixed for redemption; (iii) the close of business on the day prior to a Bond holder giving notice of redemption in accordance with the conditions; and (iv) the giving of notice by the trustee that the Bonds are accelerated by reason of the occurrence of an event of default. Upon conversion, the Bond holder is entitled to receive ordinary shares at the conversion price of $32.83 per ordinary share, (subject to adjustment as outlined below). The conversion price is subject to adjustment in respect of (i) any dividend or distribution by the Company, (ii) a change of control and (iii) customary anti-dilution adjustments for, inter alia, share consolidations, share splits, spin-off events, rights issues, bonus issues and reorganizations. The initial conversion price of $33.5879 was adjusted to $33.17 with effect from March 11, 2009 as a result of cumulative dividend payments during the period from October 2007 to April 2009 inclusive and to $32.83 with effect from March 11, 2011 as a result of cumulative dividend payments during the period April 2009 to April 2011 inclusive. The ordinary shares issued on conversion will be delivered credited as fully paid, and will rank pari passu in all respects with all fully paid ordinary shares in issue on the relevant conversion date.

Convertible Bonds

12 Months Ended

Dec. 31, 2011

15. Convertible Bonds

Shire 2.75% Convertible Bonds due 2014

On May 9, 2007 Shire issued $1,100 million in principal amount of 2.75% convertible bonds due 2014 and convertible into fully paid ordinary shares of Shire plc (the “Bonds”). The net proceeds of issuing the Bonds, after deducting the commissions and other direct costs of issue, totaled $1,081.7 million. In connection with the Scheme the Trust Deed was amended and restated in 2008 in order to provide that, following the substitution of Shire plc in place of Old Shire as the principal obligor and issuer of the Convertible Bonds, the Bonds would be convertible into ordinary shares of Shire plc.

The Bonds were issued at 100% of their principal amount, and unless previously purchased and cancelled, redeemed or converted, will be redeemed on May 9, 2014 (the “Final Maturity Date”) at their principal amount.

The Bonds bear interest at 2.75% per annum, payable semi-annually in arrears on November 9 and May 9. The Bonds constitute direct, unconditional, unsubordinated and unsecured obligations of the Company, and rank pari passu and ratably, without any preference amongst themselves, and equally with all other existing and future unsecured and unsubordinated obligations of the Company.

The Bonds may be redeemed at the option of the Company, at their principal amount together with accrued and unpaid interest if: (i) at any time after May 23, 2012 if on no less than 20 dealing days in any period of 30 consecutive dealing days the value of Shire's ordinary shares underlying each Bond in the principal amount of $100,000 would exceed $130,000; or (ii) at any time conversion rights have been exercised, and/or purchases and corresponding cancellations, and/or redemptions effected in respect of 85% or more in principal amount of Bonds originally issued. The Bonds may also be redeemed at the option of the Bond holder at their principal amount including accrued but unpaid interest on May 9, 2012 (the “Put Option”), or following the occurrence of a change of control of Shire. The Bonds are repayable in US dollars, but also contain provisions entitling the Company to settle redemption amounts in Pounds sterling, or in the case of the Final Maturity Date and following exercise of the Put Option, by delivery of the underlying ordinary shares and a cash top-up amount. In accordance with US GAAP, as the exercise of the Put Option could require the Company to redeem the Bonds within twelve months of the balance sheet date, the Bonds have been presented as a current liability at December 31, 2011.

The Bonds are convertible into ordinary shares during the conversion period, being the period from June 18, 2007 until the earlier of: (i) the close of business on the date falling fourteen days prior to the Final Maturity Date; (ii) if the Bonds have been called for redemption by the Company, the close of business fourteen days before the date fixed for redemption; (iii) the close of business on the day prior to a Bond holder giving notice of redemption in accordance with the conditions; and (iv) the giving of notice by the trustee that the Bonds are accelerated by reason of the occurrence of an event of default.

Upon conversion, the Bond holder is entitled to receive ordinary shares at the conversion price of $32.83 per ordinary share, (subject to adjustment as outlined below).

The conversion price is subject to adjustment in respect of (i) any dividend or distribution by the Company, (ii) a change of control and (iii) customary anti-dilution adjustments for, inter alia, share consolidations, share splits, spin-off events, rights issues, bonus issues and reorganizations. The initial conversion price of $33.5879 was adjusted to $33.17 with effect from March 11, 2009 as a result of cumulative dividend payments during the period from October 2007 to April 2009 inclusive and to $32.83 with effect from March 11, 2011 as a result of cumulative dividend payments during the period April 2009 to April 2011 inclusive. The ordinary shares issued on conversion will be delivered credited as fully paid, and will rank pari passu in all respects with all fully paid ordinary shares in issue on the relevant conversion date.