Borrowings (Details) (USD $)	0 Months Ended
	Nov. 11, 2013 contract	Feb. 11, 2015	Dec. 12, 2014	Dec. 31, 2014	Feb. 23, 2015
2013 Facilities Agreement
Line of Credit Facility [Line Items]
Facilitiy agreement total amount	$ 850,000,000
Covenant terms	The 2013 Facilities Agreement includes customary representations and warranties, covenants and events of default, including requirements that the ratio of Net Debt to EBITDA of Shire (each as defined in the 2013 Facilities Agreement) must not, at any time, exceed 3.5:1 for the Relevant Period (as defined in the 2013 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 2013 Facilities Agreement) must not be less than 4.0:1.
Number of term loan facilities	2
Current borrowing outstanding				850,000,000
Facility amount outstanding				850
Interest rate description	The interest rate applicable to the $850 million term loan facility commenced at LIBOR plus 1.15% per annum until delivery of the compliance certificate for the year ended December 31, 2013 and is subject to change depending upon the prevailing ratio of Net Debt to EBITDA of the Group (each as defined in the 2013 Facilities Agreement), in respect of the most recently completed financial year or financial half year.
Borrowings, Option Covenant,Net Debt to EBITDA	3.5
Line of Credit Facility, Margin Interest Rate	1.15%
2015 Facilities Agreement
Line of Credit Facility [Line Items]
Facilitiy agreement total amount		850,000,000
2015 Facilities Agreement | New 2015 facililites agreement
Line of Credit Facility [Line Items]
Facility agreement initiation date		Jan. 11, 2015
Facility agreement expiration date		Jan. 10, 2016
Rate of commitment fee		35.00%
Covenant terms		The 2015 Facility 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 2015 Facility Agreement) must not, at any time, exceed 3.5:1 for the Relevant Period (as defined in the 2015 Facility Agreement), except that following certain acquisitions, including the merger with NPS Pharma, 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 2015 Facility Agreement) must not be less than 4.0:1.
Commitment fee description		Shire shall also pay a commitment fee on the available but unutilized commitments under the 2015 Facility Agreement for the availability period applicable to each facility. With effect from first utilization, the commitment fee rate will be 35% of the applicable margin. 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.
Facility amount outstanding		850,000,000			850,000,000
Interest rate description		Interest on any loans made under the 2015 Facility Agreement 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 2015 Facility Agreement is LIBOR plus 0.50% per annum and increases by 0.25% per annum 6 months after the date of the agreement and on each subsequent date falling at three months intervals thereafter.
Borrowings, Option Covenant,Net Debt to EBITDA		3.5
Line of Credit Facility, Margin Interest Rate		0.50%
Line of Credit Facility, Margin Interest Rate Per Annum Increase		0.25%
Maturity extension option		6 months
Line of Credit Facility, Period over which commitment rate will increase		3 months
Minimum | 2013 Facilities Agreement
Line of Credit Facility [Line Items]
Borrowings, Option Covenant,Net Debt to EBITDA	4.0
Minimum | 2015 Facilities Agreement | New 2015 facililites agreement
Line of Credit Facility [Line Items]
Rate of commitment fee		0.00%
Borrowings, Option Covenant,Net Debt to EBITDA		4.0
Maximum | 2015 Facilities Agreement | New 2015 facililites agreement
Line of Credit Facility [Line Items]
Rate of commitment fee		35.00%
Term loan facility one | 2013 Facilities Agreement
Line of Credit Facility [Line Items]
Term loan facility	1,750,000,000
Term loan facility one | 2015 Facilities Agreement | New 2015 facililites agreement
Line of Credit Facility [Line Items]
Term loan facility		850,000,000
Term loan facilitly two | 2013 Facilities Agreement
Line of Credit Facility [Line Items]
Facility agreement expiration date	Nov. 11, 2015
Term loan facility	850,000,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Facility agreement initiation date			Dec. 12, 2014
Facilitiy agreement total amount			2,100,000,000
Facility agreement expiration date			Dec. 12, 2019
Rate of commitment fee			35.00%
Covenant terms			The RCF includes customary representations and warranties, covenants and events of default, including requirements that Shire’s (i) ratio of Net Debt to EBITDA in respect of the most recently-ended 12-month Relevant Period (each as defined in the RCF) must not, at any time, exceed 3.5:1 (except that, following an acquisition fulfilling certain criteria, Shire may on a once only basis elect to increase this ratio to 4.0:1 for the Relevant Period in which the acquisition was completed and for that immediately following) and (ii) ratio of EBITDA to Net Interest for the most recently-ended 12-month Relevant Period (each as defined in the RCF) must not be less than 4.0:1.
Commitment fee description			Shire shall also pay (i) a commitment fee equal to 35% per year of the applicable margin on available commitments under the RCF for the availability period applicable thereto and (ii) a utilization fee equal to (a) 0.10% per year of the aggregate of the amount requested by the borrower in a utilization request (the “Base Currency Amount”) of all outstanding loans up to an aggregate Base Currency Amount equal to $700 million, (b) 0.15% per year of the amount by which the aggregate Base Currency Amount of all outstanding loans exceeds $700 million but is equal to or less than $1,400 million and (c) 0.30% per year of the amount by which the aggregate Base Currency Amount of all outstanding loans exceeds $1,400 million.
Swingline Facility			250,000,000
Facility amount outstanding					1,300,000,000
Interest rate description			Interest on any loans made under the RCF 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 for the RCF will be: LIBOR (or, in relation to any revolving loan in euro, EURIBOR); plus 0.30% per year until delivery of the first compliance certificate required to be delivered after the date of the RCF, subject to change thereafter depending upon (i) the prevailing ratio of Net Debt to EBITDA (each as defined in the RCF) in respect of the most recently completed financial year or financial half year and (ii) the occurrence and continuation of an event of default in respect of the financial covenants or the failure to provide a compliance certificate.
Borrowings, Option Covenant,Net Debt to EBITDA			3.5
Line of Credit Facility, Margin Interest Rate			0.30%
Revolving Credit Facility | 2013 Facilities Agreement
Line of Credit Facility [Line Items]
Facility agreement initiation date	Nov. 11, 2013
Facilitiy agreement total amount	$ 2,600,000,000
Revolving Credit Facility | Base Currency Amount Equal to $700million
Line of Credit Facility [Line Items]
Rate of utilization fee			0.10%
Revolving Credit Facility | Base Currency amount exceeds $700m but equal or less than $1400m
Line of Credit Facility [Line Items]
Rate of utilization fee			0.20%
Revolving Credit Facility | Base currency amount exceeds $1400m
Line of Credit Facility [Line Items]
Rate of utilization fee			0.30%
Revolving Credit Facility | Minimum
Line of Credit Facility [Line Items]
Borrowings, Option Covenant,Net Debt to EBITDA			4.0