Document and Entity Information (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Oct. 26, 2012	Jun. 30, 2012
Document and Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Sep. 30, 2012
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0000936402
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Registrant Name	Shire plc
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding		562.5
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3
Entity Public Float			$ 15,993