Other long-term debt (Details) (USD $)	12 Months Ended
	Dec. 31, 2013 contract
Line of Credit Facility [Line Items]
Facility agreement initiation date	Nov. 11, 2013
Interest rate description	Interest on any loans made under the facilities will be payable on the last day of each interest period, which may be one week or one, two, three or six months at the election of Shire, or as otherwise agreed with the lenders. The interest rate applicable to the $0.55 billion term loan facility is LIBOR plus 0.75% per annum and increases by 0.25% per annum on August 11, 2014 and on three-month intervals thereafter. The interest rate applicable to the $0.85 billion term loan facility commenced at LIBOR plus 1.15% per annum until delivery of the compliance certificate for the year ending December 31, 2013 and thereafter is subject to change depending upon the prevailing ratio of Net Debt to EBITDA of the Group (each as defined in the Facilities Agreement), in respect of the most recently completed financial year or financial half year. 17.        Other non-current liabilities
Rate of commitment fee	35.00%
Covenant terms	The Facilities Agreement includes customary representations and warranties, covenants and events of default, including requirements that the ratio of Net Debt to EBITDA of the Group (each as defined in the Facilities Agreement) must not, at any time, exceed 3.5:1 for the Relevant Period (as defined in the Facilities Agreement), except that following certain acquisitions, including the ViroPharma acquisition, Shire may elect to increase the ratio to 4.0:1 in the relevant period in which the acquisition was completed and the immediately following relevant period. In addition, for each 12-month period ending December 31 or June 30, the ratio of EBITDA of the Group to Net Interest (each as defined in the Facilities Agreement) must not be less than 4.0:1. The Facilities Agreement restricts (subject to certain covenants) Shire’s ability to incur additional financial indebtedness, grant security over its assets or provide or guarantee loans. Further, any lender may require mandatory prepayment of its participation if there is a change of control of Shire. In addition, in certain circumstances, the net proceeds of certain shares, undertakings or business disposals by Shire must be applied towards the mandatory prepayment of the facilities, subject to certain exceptions. Events of default under the facilities include: (i) non-payment of any amounts due under the facilities, (ii) failure to satisfy any financial covenants, (iii) material misrepresentation in any of the finance documents, (iv) failure to pay, or certain other defaults, under other financial indebtedness, (v) certain insolvency events or proceedings, (vi) material adverse changes in the business, operations, assets or financial condition of Shire and its subsidiaries, (vii) if it becomes unlawful for Shire or any of its subsidiaries that are parties to the Facilities Agreement to perform their obligations or (viii) if Shire or any subsidiary of Shire which is a party to the Facilities Agreement repudiates the Facilities Agreement or any other finance document, among others.The Facilities Agreement is governed by English law
Number of term loan facilities	2
Commitment fee description	Before first utilization, the commitment fee rate will increase in stages from 0% to 35% of the applicable margin over a period of 3 months.
Minimum commitment fee
Line of Credit Facility [Line Items]
Rate of commitment fee	0.00%
Maximum commitment fee
Line of Credit Facility [Line Items]
Rate of commitment fee	35.00%
Term Loan Facility One, to finance the acquisition of Viropharma and for the redemption of Shire's Bonds
Line of Credit Facility [Line Items]
Facility agreement expiration date	Nov. 10, 2014
Term loan facility	$ 550,000,000
Option to extend the maturity of credit facility	364 days
Term Loan Facilitly Two, to finance the acquisition of Viropharma only
Line of Credit Facility [Line Items]
Facility agreement expiration date	Nov. 11, 2015
Term loan facility	850,000,000
Original facility
Line of Credit Facility [Line Items]
Facilitiy agreement total amount	2,600,000,000
Original facility | Term Loan Facility One, to finance the acquisition of Viropharma and for the redemption of Shire's Bonds
Line of Credit Facility [Line Items]
Term loan facility	1,750,000,000
Original facility | Term Loan Facilitly Two, to finance the acquisition of Viropharma only
Line of Credit Facility [Line Items]
Term loan facility	850,000,000
Revised facility
Line of Credit Facility [Line Items]
Facilitiy agreement total amount	1,400,000,000
Revised facility | Term Loan Facility One, to finance the acquisition of Viropharma and for the redemption of Shire's Bonds
Line of Credit Facility [Line Items]
Term loan facility	550,000,000
Revised facility | Term Loan Facilitly Two, to finance the acquisition of Viropharma only
Line of Credit Facility [Line Items]
Term loan facility	$ 850,000,000