Taxation (Pretax Income from Continuing Operations and Provision for Income Taxes) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Components of pre tax income from continuing operations
Republic of Ireland	$ (65.9)		$ (170.0)		$ (232.3)
UK	45.3		35.4		62.8
US	747.6		745.5		552.2
Other jurisdictions	363.1		158.4		260.3
Income from continuing operations before income taxes and equity in earnings/(losses) of equity method investees	1,090.1		769.3		643.0
Current income taxes:
Republic of Ireland, current	(1.8)		0		0
US federal tax, current	193.1		176.4		154.3
US state and local taxes, current	9.0		6.6		14.4
Other, current	40.0		25.9		16.8
Total current taxes	240.3		208.9		185.5
Deferred taxes:
Republic of Ireland, deferred					(1.0)
US federal tax, deferred	22.5		(6.0)		(24.5)
US state and local taxes, deferred	(4.6)		(9.8)		(32.2)
UK corporation tax, deferred	(1.0)		(0.1)		6.1
Other, deferred	(29.6)		(10.3)		4.6
Total deferred taxes	(12.7)		(26.2)		(47.0)
Total income taxes	$ 227.6	[1]	$ 182.7	[1]	$ 138.5	[1]

[1] Total income taxes relate solely to continuing operations as there is no tax provision/(benefit) relating to discontinued operations for the years to December 31, 2011, 2010 or 2009.