Taxation (Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Reconciliation of Unrecognized Tax Benefits
Balance at January 1,	$ 290.8	[1]	$ 254.0	[1]	$ 228.7
Increases based on tax positions related to the current year	18.2		12.4		4.2
Decreases based on tax positions taken in the current year	(2.5)		(1.7)		(0.2)
Increases for tax positions taken in prior years	1.4		18.0		25.2
Decreases for tax positions taken in prior years	(12.0)		(3.2)		(19.4)
Decreases resulting from settlements with the taxing authorities	(25.7)		(6.5)		(16.1)
Decreases as a result of expiration of the statute of limitations	(0.5)		0		0
Foreign currency translation adjustments	(4.2)	[2]	17.8	[2]	31.6	[2]
Balance at December 31,	265.5	[1]	290.8	[1]	254.0	[1]
Income tax penalties and interest expense	4.0		1.0		21.3
Income tax penalties and interest expense accrued	$ 114.5		$ 110.5

[1] The full amount of which would affect the effective rate if recognized

[2] Recognized within Other Comprehensive Income