Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Statement of Income and Comprehensive Income [Abstract]
Net income	$ 865.0	$ 588.0	$ 491.4
Other comprehensive income:
Foreign currency translation adjustments	(24.0)	(51.3)	35.2
Unrealized holding gain/(loss) on available-for-sale securities (net of taxes of $0.2 million, $nil and $2.6 million)	16.2	(13.6)	16.1
Other than temporary impairment of available-for-sale securities, net of taxes	2.4	1.5	0.8
Realized gain on divestment of available-for-sale securities, net of taxes	(20.0)	0	0
Comprehensive income	839.6	524.6	543.5
Add: net loss attributable to the noncontrolling interest in subsidiaries	0	0	0.2
Comprehensive income attributable to Shire plc	839.6	524.6	543.7
Components of accumulated other comprehensive income
Foreign currency translation adjustments	61.4	85.4
Unrealized holding (loss)/ gain on available-for-sale securities, net of taxes	(1.1)	0.3
Accumulated other comprehensive income	$ 60.3	$ 85.7