Consolidated Statements of Changes in Equity (USD $) In Millions	Total USD ($)	Common Stock USD ($)	Common Stock (Shares)	Additional Paid-in Capital USD ($)	Treasury Stock USD ($)	Accumulated Other Comprehensive Income USD ($)	Retained earnings/ (accumulated deficit) $'M USD ($)
Stockholders' equity, beginning balance at Dec. 31, 2010	$ 2,451.4	$ 55.7		$ 2,746.4	$ (276.1)	$ 85.7	$ (160.3)
Common stock outstanding, beginning balance at Dec. 31, 2010	562.2		562.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	609.7						609.7
Foreign currency translation	4.6					4.6
Options exercised	0.9			0.9
Options exercised, shares			0.3
Share-based compensation	55.9			55.9
Excess tax benefit associated with exercise of stock options	21.3			21.3
Shares purchased by Employee Share Ownership Trust ("ESOT")	(126.8)				(126.8)
Shares released by ESOT to satisfy exercise of stock options	0				109.8		(109.8)
Unrealized holding gain/(loss) on available-for-sale securities (net of taxes of $0.3 million, $nil, $0.2 million and $2.6 million)	15.8					15.8
Realized gain on available-for-sale securities, net of taxes	(20.0)					(20.0)
Other than temporary impairment of available-for-sale securities	2.4					2.4
Dividends	(60.5)						(60.5)	[1]
Stockholders' equity, ending balance at Sep. 30, 2011	$ 2,954.7	$ 55.7		$ 2,824.5	$ (293.1)	$ 88.5	$ 279.1
Common stock outstanding, ending balance at Sep. 30, 2011	562.5		562.5

[1] Dividends per share During the nine months to September 30, 2011 Shire plc declared and paid dividends of 10.85 US cents per ordinary share (equivalent to 32.55 US cents per ADS) totalling $60.5 million