Other Intangible Assets, Net (Roll Forward) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Other Intangible Assets [Roll Forward]
As at January 1,	$ 2,493.0	$ 1,978.9
Acquisitions	22.0	0
Amortization charged	(45.8)	(36.1)
Foreign currency translation	19.8	43.0
As at March 31,	$ 2,489.0	$ 1,985.8