Document and Entity Information (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Feb. 21, 2012	Jun. 30, 2011
Document and Entity Information [Abstract]
Document Type	10-K
Document Period End Date	Dec. 31, 2011
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	2011
Document Fiscal Period Focus	FY
Entity Public Float			$ 17,197