Goodwill (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Goodwill [Line Items]
Goodwill arising on business acquired	$ 1,773.8	$ 170.3
Goodwill [Roll Forward]
As at January 1,	624.6	644.5
Acquisition	1,773.8	170.3
Goodwill impairment charge		(198.9)
Foreign currency translation	(24.7)	5.4
As at September 30,	2,373.7	621.3
Continung operations
Goodwill [Roll Forward]
Goodwill impairment charge	0	(7.1)
Discontinued operations
Goodwill [Roll Forward]
Goodwill impairment charge	$ 0	$ (191.8)